PRODUCING - Alabama Cooperative Extension System

CIRCULAR ANR-327
PRODUCING
Channel Catfish Fingerlings
ALABAMA COOPERATIVE EXTENSION SERVICE
AUBURN UNIVERSITY
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AUBURN UNIVERSITY

CIRCULAR ANR-327
PRODUCING
Channel Catfish Fingerlings
CATFISH HATCHERIES range from relatively
simple, open-pond spawning systems to complex
systems where eggs are incubated in troughs, depending
on the size and purpose of the operation.
Private hatcheries supply channel catfish fingerlings
for commercial food fish production, recreational
fee-fishing and home-use. Some hatcheries
sell fingerlings to other producers, while
others limit their operations to supplying their
own needs. A careful study of the market should
be conducted before investing in catfish fingerling
production to avoid losses caused by insufficient
demand.
Whatever the size or purpose of the operation,
there must be a sufficient supply of good quality
water and the soil and terrain must be suitable
for pond construction.
Success in fingerling production ca,lls for
healthy, disease-free catfish brood stock, suitable
ponds for holding brood stock and, in most cases,
nursery ponds for rearing fingerlings. Commercial
fingerling producers usually have separate
hatchery troughs and tanks where eggs are incubated
and the newly hatched fish, called fry, are
trained to feed before they are stocked into nursery
ponds. Tanks equipped with a dependable
water supply and aeration are needed to hold and
grade fingerlings before shipment. Seines of suitable
mesh size, length and depth and a fish transporter
are needed to harvest and transport fry
and fingerlings.
- Water of sufficient quantity and quality is critical
for all hatchery systems. The water supply
must be free of contamination such as pesticides.
JoHN JENSEN, Fisheries Specialist, Alabama Cooperative
Extension Service
REx DuNHAM, Assistant Professor, Department of Fisheries
and Allied Aquacultures, School of Agriculture,
Forestry and the Biological Sciences and the Alabama
Agricultural Experiment Station I
JoHN FLYNN, formerly Graduate Aide-Fisheries, Alabama
Cooperative Extension Service
AUBURN UNIVERSITY
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Total alkalinity and total hardness should exceed
20 parts per million, and the pH should range between
6.5 and 8.0. Acid and soft pond water can
usually be corrected with agricultural limestone
to meet these requirements. The conditioning of
well water can be more difficult. Your county Extension
agent can assist in getting your water
tested.
Catfish fingerling production requires more
technical skill and management than producing
food-size fish from fingerlings. The fingerling
producer manages the reproductive behavior of
the catfish brood stock to meet his needs. The objective
is to produce a given number of fingerlings
of a certain size by a specified time. This requires
careful planning, a good understanding of the catfish
reproductive process and selection of an appropriate
production system. Most successful operations
start small and expand as the operator
gains experience.
Brood Stock Selection
Cattle and hog producers recognize that the
quantity and quality of young animals produced
is directly related to the selection and care of
brood animals. Likewise, successful fingerling
Figure 1. Healthy brood fish in the 3 to 10 pound size range are
needed to produce abundant, healthy fingerlings.

producers select the best brood fish and care for
them properly.
Channel catfish generally reach prime breeding
condition in three to four years. Fish less than
four years old are unreliable spawners. Only 20
percent of two-year-old fish can be expected to
spawn. A 40 percent spawning rate for threeyear-old
fish is considered good. Catfish are prime
spawners at four years. With good care, high
spawning rates of about 50 percent are common.
Fish older than six years become too large to handle
easily.
SOURCES AND SELECTION FACTORS
You may want to buy mature fish nearly ready
to spawn rather than waiting for fingerlings to
reach spawning age. The desirable size for brood
fish is 3 to 10 pounds if the fish have had proper
care ( Figure 1 ) .
Probably the best source of brood fish is a
reputable hatchery. However, be careful not to
buy culls. Fish-fanning trade magazines often
carry advertisements for brood stock. Some growers
may have oversized food fish that make good
brood stock. Catfish processors sometimes harvest
large fish and sell them for brood stock.
A void fish recently taken from the wild. They
are often unreliable spawners, and their fingerlings
may grow more slowly and be more susceptible
to disease than fingerlings from established
hatchery stocks.
A void a source having a history of channel
catfish virus disease. This disease can be spread
from the brood stock to all the catfish on your
farm. Check the brooders thoroughly before buying.
The fish should be full-bodied and free of
sores or hemorrhages on the skin. Thin fish may
be old, diseased or underfed.
Be certain that you get enough males and females.
A ratio of about three females for every
two males is a good mix, because one male can
mate with two or more females during a single
spawning season. Although catfish generally produce
offspring in a 50:50 sex ratio, do not take this
ratio for granted in the brooders you purchase.
Determine the sex of each fish you buy.
DETERMINING SEX
Both primary and secondary sex characteristics
are useful in telling males from females. Secondary
characteristics are those not directly related
to reproduction, such as body shape and coloration.
Males are usually larger and have broader
heads than females. As the spawning season
approaches, males become lean, develop large
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Figure 2. Just prior to sp•wnlng, females (left) develop soft, swollen
bellies and have heads narrower than their bodies. Males
(right) have large muscular heads wider than their bodies
and are often darker in color.
Figure 3. To determine sex of brood catfish look at the belly of the
fish. You will see two openings. The opening nearest the
head is the anus. The opening nearest the tail is the genital
opening. On the male (left) the genital opening looks like
a tiny raised nipple. On the female (right) the genital
opening is not raised but is oval. Just before spawning,
the genital opening of the female is often swollen and
reddish.
muscular heads, and sometimes become darker.
Females' heads are narrower than their bodies
when viewed from above. They also develop soft,
swollen bellies (Figure 2).
Always confirm sex by examining the genitals,
the primary sex characteristic. This is particularly
important with young fish and during the
non-spawning season when secondary sex characteristics
are less pronounced. Experienced operators
can sex fish as small as one pound by examining
the genitals.
Turn the fish belly up to examine the genitals.
Two or three openings are present (Figure 3).

The opening nearest the head is the anus, while
the one nearest the tail is the genital opening. The
genital opening of the male is at the end of a
fleshy, nipple-like structure called the genital papilla.
The papilla usually becomes swollen and
rigid as spawning season approaches. The genital
area of the female catfish is oval and flat and has
two openings separated by a small flap of skin. A
slit or groove is located at the head end of the
genital area. A small urinary opening is located
at the tail end. The female genital area often becomes
red, swollen and covered with mucus as
spawning time approaches. Sometimes a pulsating
of the genital area can be seen.
A probe can be used to distinguish the sexes,
particularly in young fish or those not in spawning
condition. A sharp pencil or straw works well.
Hold the fish belly up with one hand grasping the
head and the other hand clasping the fish firmly
at the tail region. This helps immobilize the fish.
With the fish's head just below your chest and
the tail held away from your body, arch the fish's
belly upward. This action causes the male papilla
or female genital slit to become more visible.
Then have an assistant gently slide the probe
over the genital area toward the tail, with the
point leading the probe. If the point of the probe
catches in the genital opening, the fish is a female
(Figure 4).
Brood Stock Management
NUTRITION
Good nutrition is essential to successful spawning.
In warm weather feed a nutritionally complete
diet containing at least 36 percent protein
at about 2 percent of the fishes' body weight daily
(Table 1). Feeding is unnecessary when water
temperature is below 55°F. When water tempera-
Figure 4. Use a probe to distinguish sexes when brood fish ••• not
in spawning condition.
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Ingredient
Soybean meal ( 44% protein)
Ground corn
\i\Theat shorts
Distillers dried solubles
Fish meal
Animal fat
Pellet binder
Dicalcium phosphate
Vitamin premix
Coated vitamin C
Trace mineral mix
Table 1. BRooD FisH DIET.
Analysis:
Total crude protein
Digestible energy
Energy to protein ratio ( kcal/ g),
Percent of total
50.5
14.93
6.0
7.5
15.0
3.0
2.5
0.5
0.75
0.057
0.075
35.6%
2640 kcal/kg
7.3:1.0
ture is between 55°F and 70°F, feed approximately
one percent of the fishes' body weight three
days per week. Estimate the amount to feed by
observing feeding vigor. Offer all the fish will eat
in about 10 minutes during warm weather. Feeding
activity slows greatly with the onset of the
spawning season.
STOCKING DENSITIES
Total weight of brood fish should not exceed
1200 pounds per acre at any time of the year.
Therefore, stock brood ponds at about 600 to 800
pounds of fish per acre. This will allow for weight
gain. For good spawning success they should gain
about 50% of their weight from one spawning season
to the next. Each year unwanted brood fish
should be culled and substituted. By replacing
old fish with young fish the total initial stocking
rate can be maintained.
The most convenient size for a brood pond is
from one to five acres. The extreme temperature
changes in very small ponds can reduce spawning
activity and harm spawned eggs. Ponds over five
acres, on the other hand, are more difficult to
manage.
Be sure to keep brood fish in more than one
pond. This minimizes the risk of losing your entire
stock to a catastrophe such as low oxygen or
disease.
Spawning Management
Spawning ponds should be stocked with not
more than 1200 pounds of brood fish per acre.
Spawning activity usually begins when the water
temperature reaches about 75°F in the spring.
Males nest in hollow logs or similar protected
places in nature. Females are attracted to the
nests and mating begins. Females deposit a layer
of eggs which are fertilized by the male. This

Figure 5. Eggs are laid in a jelly-like mass of up to 4,000 eggs per
pound of female body weight.
process is repeated over several hours until a
jelly-like egg mass of up to two to three pounds,
depending on fish size, is deposited (Figure 5).
Female catfish usually produce from 2,000 to
3,000 eggs per pound of body weight when they
reach five pounds. Smaller females produce up to
4,000 eggs per pound of body weight. The male
guards the eggs, fanning them with his pelvic fins
and tail to force oxygen-rich water into the mass.
USE OF SPAWNING CONTAINERS
Spawning containers should be provided.
Some materials used are milk cans, nail kegs,
earthen crocks, ammunition cans and wooden
boxes. The spawning container must be large
enough to accommodate the brooding pair. The
opening should be just large enough for them to
enter (Figure 6).
Place the containers in one to two and a half
feet of water, one to ten yards apart with the open
end toward the pond center (Figure 7). Mark
each one with a float so that it can be found. Provide
containers for 50 to 90 percent of the brooding
pairs.
Wait until the water temperature reaches 75°F
before putting out the spawning containers. This
discourages early spawning. Gradually move the
containers to deeper, cooler water as the water
warms. However, do not use this technique if the
water becomes stratified by temperature and
oxygen.
Spawning activity sometimes diminishes for
no apparent reason. Lowering the water level
about a foot and rapidly refilling the pond may
encourage additional spawning. Moving the
spawning containers may also stimulate spawning.
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Figure 6. Spawning containers:
a) galvanized ammo can with hinged lid.
b) plastic buckets joined together.
c) wooden box to be staked to pond bottom.

Figure 7. Sp•wning boxes in position.
Considering that not all females spawn and
not all of the eggs, fry and fingerlings survive, estimate
that about 800 to 1,000 fingerlings will be
produced per pound of healthy female brooder.
SPAWNING METHODS
Three methods for spawning channel catfish
allow the fish to spawn naturally in the pond. ·Pen
spawning is used for mating selected pairs.
SPAWNING/REARING PoND METHOD. This approach
requires the least skill, labor and facilities.
However, it is unreliable and not recommended
for commercial operations. Place the spawning
containers in the pond and allow the fish to spawn
naturally. The male hatches the eggs in the container
and the fry remain in the pond.
Drain the pond to harvest fingerlings using a
seine, or trap them as needed, using a technique
described later. The operator using this method
does not know the quantity of fingerlings present
until harvest. Survival of fry is usually poor with
this technique because it is difficult to control disease,
aquatic insects and wild fish that eat fry.
FRY TRANSFER METHOD, OPEN PoND SPAWNING.
The fry transfer method is more productive than
the spawning/rearing pond method but requires
more skill and labor. The newly-hatched fry are
transferred from the spawning container to previously
prepared nursery ponds. Check spawning
containers every three days. When an egg mass is
found, gently pinch off a clump of 6 to 10 eggs
from the edge. Determine the age of the eggs
to predict the hatching date (Table 2).
Allow the male to incubate the eggs. Remove
the fry one day after the predicted hatching date.
The male catfish is capable of inflicting painful
bites to hands and bare feet, so chase him from
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Table 2. EsTIMATING" THE AcE oF CATFISH EGGS.
Egg description
No pulsation
Pulsating motion
Bloody streak
Blood throughout egg
Eyes visible
Eyes visible, embryo turns inside shell
Complete fish visible, no bloody streak
Hatching begins
Estimated age
(water at 78°F)
Less than 24 hours
1 to 2 days
2 to 3 days
3 to 4 days
4 to 5 days
5 to 6 days
6 to 7 days
7 to 8 days
Note: For every 2°F above or below 78°F, subtract or
add one day, respectively, to hatching time.
Source: Howard P. Clemens and Kermit E. Sneed, 1957.
Spawning behavior of the channel catfish Ictalurus
punctatus. Special Scientific Report-Fisheries
No. 219. U.S. Department of Interior, Fish and
Wildlife Service.
the spawning container using a stick or gloved
hand or lift the container gently off the pond bottom
until he exits.
Transfer the fry to a bucket containing pond
water by gently pouring them from the spawning
container. Release the fry into the nursery pond
by slowly submerging the bucket, allowing them
to escape into the pond near a shelter. The spawning
container can be moved to the nursery pond
and left for shelter.
If the water temperature is not the same in
both ponds, the fry must be slowly acclimated to
the nursery pond temperature before stocking.
When temperature differences are more than two
to three degrees, slowly replace water in the
bucket with nursery pond water until the water
temperature is equalized.
EGG TRANSFER METHOD, OPEN POND SPAWNING.
Egg transfer is the most productive of the three
methods but also requires the most skill, labor and
facilities. The fish are allowed to spawn in the
containers as with the other methods, but the eggs
are removed and incubated in a hatchery.
Check the spawning containers every two to
four days. Late morning is the best time, because
most spawning probably occurs at night or early
morning. Checking at this time thus does not interrupt
spawning activity and allows for timely
removal of eggs. Remove eggs immediately after
finding them. Disturbed brood fish may sometimes
eat eggs or dislodge them.
The egg mass sticks to the container floor.
Gently scrape it from the container with a plastic
credit card, kitchen spatula or similar device (Figure
8). Float the egg mass into a bucket and car-

Figure I. Treat egg ma•M• gently.
Figura 9. Spawning pans for mating selected pairs.
ry it immersed in water to the hatchery. Eggs can
be left in buckets in a shaded area for up to 15
minutes, but no longer unless aeration is used.
Eggs must be shielded from sunlight. Egg masses
near hatching must be taken to the hatchery immediately
because they require more oxygen than
young or "green" egg masses.
PEN SPAWNING. Pen spawning, a modification
of the previously described methods, is used mainly
for mating selected pairs. Construct pens next
to the pond bank, using plastic-coated wire or
other non-rusting materials. Mesh should be
large enough to allow water to circulate, but not
so large as to allow brood fish to escape. Mesh
size from one-half to two inches is satisfactory. A
pen 4 X 6 feet is adequate. Adjacent pens can
have common sides, to minimize construction
costs ( Figure 9) .
Place a spawning container and a ready
spawning pair in each pen. The fish should be
about equal in size. Check pens from the bank
daily for welfare of the brooders. Remove females
that are being harassed or injured by the male
fish. Remove the female immediately after spawning
to keep her from being injured or killed by the
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aggressive male. Do not place more than one female
in the pen at a time, as this can lead to fighting
and injury to the females. Eggs can be left
with the male or taken to the hatchery to incubate.
If spawning does not occur in 10 to 14 days,
check the sexes of the pair and exchange brood
fish if needed.
The Hatchery
In maximum-production systems, eggs are
transferred to a special hatchery, and incubated
and the fry started on food before they are
moved into nursery ponds. The hatchery need
not be elaborate. Some of the equipment can be
built by the operator. The critical ingredient is
a water supply of the right quality and quantity.
WATER QUALITY
Water temperature must be between 75°F and
85°F for proper hatching. Because eggs and fry
have high oxygen requirements, maintain oxygen
levels at a minimum of six parts per million. Water
pH must be between 6.5 and 8.0 for best results.
Risk of disease is less if there are no fish in the
water supply. Keep water as clean and free of organic
matter such as algae and decaying leaves as
possible. A water flow of about five gallons per
minute is needed for one hatching trough.
Well water is probably best for use in the
hatchery. It is usually clean and free of disease
organisms. vVell water, however, is generally too
cold for optimum hatching. It can be warmed in
a conventional water heater or stored and warmed
in a small pond built specifically for this purpose.
Well water contains very little oxygen. Splash
it over a cascade or through screens to add oxygen.
Storing well water in a pond before use also
increases oxygen content. Well water with a high
iron content should be aerated in a settling tank or
reservoir pond before distribution to the hatchery.
Some hatcheries receive water directly from
production ponds. Pond water is usually the
proper temperature for incubation, but may present
other problems. Disease organisms can be
introduced to the hatchery from the pond, especially
if fish are present. Algae, suspended mud
particles, and other materials in pond water can
accumulate on eggs and smother them. The oxygen
content of ponds often fluctuates, and low
oxygen levels, two to three parts per million (ppm),
are especially dangerous to fish eggs and fry.
INCUBATION TROUGH CONSTRUCTION
Eggs are commonly incubated in wooden, fiberglass
or metal troughs about 8 feet long, 18 to

24 inches wide and 10 to 12 inches deep. A series
of paddles attached to a shaft are suspended in
the trough (Figure 10). Paddles are spaced to
.allow wire-mesh baskets holding the egg masses to
fit between them. The paddles should reach about
halfway to the bottom of the trough and should
extend below the bottoms of the baskets. Baskets
are made from one-fourth inch hardware cloth
Figure 10. Space paddles so that bukets holding eggs will fit be·
tween them.
Figure 11. Construct baskets of one-fourth inch h.,dwere cloth.
(Figure 11). An electric motor with a gear reduction
attachment turns the paddles at 30 rpm. This
motion gently rocks the egg masses and causes
oxygen-rich water to flow through them. An 8-foot
trough can hold six to eight egg baskets (Figure
12).
Water enters one end of the trough at five gallons
per minute. A standpipe fitted into a drain
at the other end controls water depth. Place window
screen over the standpipe to prevent fry from
escaping.
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Figure 12. An 8·foot paddlewheel trough can hold 6 to 8 baskets
containing 12 to 16 egg masses, depending on water flow
and egg mass size.
DISEASE CONTROL
Bacterial diseases and fungus infections are
constant threats to eggs. The best disease control
is prevention. A clean water supply and frequent
scrubbing and disinfection of troughs and equipment
are essential. Remove debris and egg shells
regularly with a siphon.
Various chemical treatments are routinely
used to prevent or treat bacterial infection (Table
3). Treat the eggs when they are removed from
the spawning container and once or twice daily
until they hatch. Distribute the proper amount
of chemical evenly along the length of the hatching
trough. Check the eggs for egg rot and fungus
and gently shake and turn them over two to three
times daily.
Bacterial egg rot appears as a milky-white
dead patch, usually on the underside and center
of the mass. Remove the infected areas immediately
and continue treating. Change the treatment
every four days to prevent a resistant bacterial
strain from developing.
Fungus grows on infertile or dead eggs. It appears
as a white or brown cotton-like growth
made of many small filaments and can invade and
kill healthy eggs. Fungus can be controlled by
treating with 100 parts per million formalin for
15 minutes. Turn the water off during treatment
but leave the paddles turning. Flush completely
with clean water when treatment time has
elapsed. Do not use the formalin treatment when
eggs are within one day of hatching.
HANDLING SAC FRY
Temperature controls incubation time (Table
2). Sac fry emerge as the eggs hatch, swim
through the screen baskets and school together in
a tight cluster on the bottom of the trough.

Figure 14. Holding boxes should be aerated by spraying water from
above.
Figure 15. A strainer placed in a bucket can be used to collect fry by
siphoning.
ated cylinder containing a pre-measured quantity
of water, taking care not to add any extra water
with the fry (Figure 17). Record the change in
water level when the fry are added. The total
number of fry can be estimated by placing all of
them in a graduated measuring container, recording
the water level change, and then comparing
the two numbers. Use this equation:
Total number of fry =
300 X change in water level with ALL fry
change in water level with 300 fry
For example, a sample you take of 300 fry
raises the water level in a 100-milliliter ( ml) graduated
cylinder from 50 to 62 ml. You will estimate
the total number of fry using a larger, wide-
Figure 16. Boxes made entirely of screen can be used to hold fry Figure 17. Count a representative sample of fry into a gradu•ted
when overhead spray is not used.
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cylinder and measure the change in volume.

Figure 18. Estimate the total number of fry by the change in water
volume in a graduated wide-mouthed container.
mouthed container also graduated in milliliters
(Figure 18). When you add all the fry, the water
level changes from 500 ml to 900 ml. Then:
300 X (900- 500)
Total number of fry=---..:,__----'-
62 -50
300 X 400
or----
12
10,000 total number of fry
FEEDING FRY
Begin feeding the fry when they first swim up
to the surface with their mouths opening and
heads moving back and forth, obviously searching
for food. "Swim-up" usually occurs about
three to four days after hatching. A high protein
diet ( 45 to 50 percent crude protein) with all essential
nutrients should be used. Recent findings
suggest that the protein should consist of about
60 percent fish meal. The food must be finely
ground so the fry can easily consume it. Commercial
fry food is usually available. Other suitable
feeds such as ground trout feed or salmon starter
can be used.
Several feeding techniques are practiced. The
dry food can be lightly sprinkled on the surface
(Figure 19). The fry will eat the portion that
floats. The food can also be moistened, formed
into a doughball and placed in the fry box or
tank. Another technique is to make a slurry and
pour it onto a plastic plate anchored to the bottom
of the fry box or tank. Feeding activity of
fry will keep the feed in suspension where it is
easily consumed.
Whatever the techniques, the fry should be
fed at least six times daily. More frequent feeding
is better. Be careful not to overfeed, how-
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ever, because wasted food will accumulate, causing
poor water quality and fungus growth. Waste
should be siphoned out and tanks and boxes
scrubbed daily. Equipment should be scrubbed
and sterilized with a 1:4,000 formalin in water solution
after each crop of fry.
Water quality in the holding facility determines
the length of time the fry can be held in
the hatchery. Fry may be held for up to 10 days
if good water quality is maintained. Water quality,
in turn, is dependent on such factors as water
flow rate, number of fry held and cleanliness
maintained.
Figure 19. Feed • finely ground feed to fry held in boxes. Siphon
wastes from boxes and tanks daily.
Fry should be eating food before they are
transferred into nursery ponds. They survive
much better in ponds when stocked as large,
strong fry.
Growing Fingerlings
The pond should be prepared to receive the
fry being grown in the hatchery. Pond preparation
is critical for good fry survival. Certain
aquatic insects and fish eat fry and must be controlled.
The "puddle" method of preparing nursery
ponds helps control insects and promotes the
growth of fish food organisms that fry will eat.
Drain and dry ponds thoroughly before stocking
the fry. Fertilize with about 100 pounds per acre
of old fish food, meat and bone meal or similar organic
material just before filling with water. Organic
fertilizer promotes growth of zooplankton,
tiny aquatic animals that are excellent fry food.
Stock the pond on the third or fourth day after the
pond begins to fill. With this method, the fry outgrow
insects and usually no special insect control

Figure 20. Insects that eat catfish fry (left to right): backswimmer,
dragonfly nymph, predaceous diving beetle. Kill back·
swimmers and diving beetles with an oil treatment. Drag·
onfly nymphs breathe with gills and are controlled by
keeping the pond dry until shortly before stocking fry.
is required. However, an independent water supply
such as a well or spring is needed to fill the
pond.
CONTROLLING INSECTS
Treatment to control insects is necessary when
the pond must be filled more than one week before
stocking ( Figure 20) . A common practice is
to spread a mixture of five to eight gallons of
diesel fuel or kerosene mixed with one quart of
motor oil per acre over the pond surface two days
before stocking. The oil film prevents air-breathing
insects from penetrating the surface to
breathe. The effectiveness of this treatment depends
on complete coverage of the pond surface
with oil. Apply oil when there is no wind or just
a light breeze. Continue this treatment for the
first two weeks at four-day intervals. A disadvantage
of this method is that it does not kill gillbreathing
insects. It also depresses oxygen levels
and inhibits zooplankton growth.
STOCKING FRY
Stock the fry while it is cool in early morning.
Gently transfer them in buckets or similar con-
Figure 21. Shelters provide areas for fry to congregate in to aid in
feeding and protection.
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tainers and slowly condition them to the pond by
gradually adding small quantities of pond water
to the fry container. Shelters such as milk cans
or frames covered with black plastic are desirable
in the ponds to improve survival and to provide
areas for fry to congregate, which aids in feeding
(Figure 21).
Stocking density depends on the size fingerlings
desired at harvest. Growth rate depends
primarily on the quantity of food the fry and fingerlings
consume if water temperature is optimum.
With very high stocking densities, it is unsafe
to feed for very long the quantity needed for
maximum fish growth, because of water quality
problems. Table 4 shows the expected fingerling
size for a 120- to 150-day growing season at different
stocking densities. V eTy good management is
needed to attain these yields.
Table 4. EsTIMATED FINGERLING SizE AFTER 120- TO 150-
DAY GROWING SEASON AT DIFFERENT STOCKING
DENSITIES.
Fry stocking density
(fish per acre)
10,000
30,000
53,000
73,000
95,000
120,000
140,000
200,000
300,000
500,000
Average length
(inches)
7-10
6-8
5-7
4-6
3-5
3-5
3-4
2-3
1-2
1
FEEDING FRY AND SMALL FINGERLINGS
Fry and small fingerlings have large appetites
and should be fed frequently, two to three times
daily for the first two weeks. Feed a finely-ground,
40 percent to 45 percent protein diet the first
three to four weeks. Recent studies suggest that
the protein should contain at least 20 percent fish
meal. Switch to small-size crumbles of more than
40 percent protein from four to six weeks of age
and then to a small pellet approximately 3/16
inch in diameter containing 36 percent protein.
Make sure that the particle size is small enough
to be swallowed by the smallest fish so that the
fingerlings grow uniformly. It is better to slightly
overfeed in the early stages to ensure that all
fry get enough food.
As the fingerlings grow, they will eat less food
in proportion to their body weight. Feed according
to Table 5. However, feeding more than 35
pounds of feed per acre per day will increase the
probability of low oxygen problems.

Table 5. SuGGESTED FEEDING RATES FOR DIFFERENT SizE CATFISH AT VARIOUS WATER TEMPERATURES MEASURED AT
ONE FooT DEEP.
Total length in
inches and average
number per pound Percent of body weight to feed daily
Average daily water 65° 67° 69° 7P 730 75° 770 79° 81°
temp. F 0 at 1 foot" -------- - - - ----- %-----------------
3" ( 100/lb) 1.5 2.4 3.6 4.8 6.0 7.2 8.4 9.6 10.8
4" (50/lb) 1.5 1.8 2.7 3.6 4.5 5.4 6.3 7.2 8.1
5" ( 31/lb) 1.5 1.5 2.2 2.9 3.6 4.3 5.0 5.8 6.5
6" (17 /lb) 1.5 1.5 1.8 2.4 3.0 3.6 4.2 4.8 5.4
7" ( 11/lb) 1.5 1.5 1.5 2.1 2.6 3.1 3.6 4.1 4.6
8" (9/lb) 1.5 1.5 1.5 1.8 2.3 2.7 3.2 3.6 4.1
9" (6/lb) 1.5 1.5 1.5 1.6 2.0 2.4 2.8 3.2 3.6
10" (3/lb) 1.5 1.5 1.5 1.5 1.8 2.2 2.5 2.9 3.2
"To obtain the average daily water temperature take temperature morning and afternoon each day and average them.
Both floating and sinking feeds are available.
Sinking feed is less expensive but floating feed allows
observation of the fingerlings. Mixing floating
feeds with the sinking type permits observation
and cuts feed costs.
Feeding activity slows considerably with cool
weather. When water temperature is 45°F to
55°F, feed five- to seven-inch fingerlings about
1.5 percent of their estimated body weight three
days per week. Fingerlings fed over winter (November
to March) in the South will gain from 25
percent to 40 percent of their initial body weight.
Smaller fingerlings need more frequent feeding
during winter. Feed them 1.5 percent of their
estimated body weight six days per week when
water temperature is between 52°F and 55°F and
three days per week when water temperature is
40°F to 52°F. Use Table 5 as a guide for feeding
fingerlings at water temperatures above 65°F.
WEED CONTROL
Aquatic weeds and pond "moss" are undesirable
in fingerling ponds. Harvesting fingerlings
is very difficult if weeds collect in seines. Excessive
aquatic weed growth also depresses oxygen
levels. Stocking 50 to 100 eight-inch grass
carp per acre is an effective weed control measure
in states where they are allowed (Figure 22).
Stock grass carp soon after the catfish fry are
stocked. Many grass carp jump over seines and
usually do not greatly interfere with fingerling
harvest.
DISEASE CONTROL
Diseases can be a serious problem for fingerling
producers. Good management, however, can
prevent many diseases, since many disease outbreaks
are related to fish stress caused by unfavor-
-14-
Figure 22. Grass carp effectively control most weeds in catfish ponds.
able environmental conditions, poor nutrition and
improper handling. When a particular disease is
diagnosed, specific treatments are available.
Some signs of diseases are changes from normal
behavior, reduced vitality, reduced feeding
activity, lazy swimming and open sores. Fish that
appear diseased should be sent immediately to a
laboratory for diagnosis. Laboratories providing
diagnostic services are listed in Appendix 2.
Select only live fish with disease signs for diagnosis.
Dead fish are unusable. Place one or two
of the smallest sick fish into a strong plastic bag.
Put in just enough water to cover the fish. Fill the
bag with pure oxygen if possible and tie securely.
Place the bag in a strong, waterproof box ( styrofoam
is best ) . Pack crushed ice in a separate
plastic bag and place this bag in the box next to
the fish (Figure 23). Ship the sample by bus or
deliver it personally. Call the laboratory to advise
them of the shipment and to provide needed information.

Figure 23. Ship diseased fish in a plutic bag with oxygen and water
packed in a styrofoam container with ice to ensure survival.
The laboratory will infonn you of the diagnosis
and recommend a treatment if needed. Chemical
treatments are generally a last resort and are
recommended when there is no alternative. Table
3 contains chemical treatment recommendations
for common fish diseases. Take every precaution
when applying chemicals. Fish have narrow
tolerance ranges for some chemicals, so very
exact calculations are needed. Determine and
record the volume of all your ponds, tanks and
troughs for reference. Calculating treatment
rates is much faster when this information is readily
available.
Some characteristics of the water may affect
the treatment rates. Analyze your water before
you treat. Copper sulfate, for example, is toxic
to catfish in very soft water. When the water has
less than 20 ppm total alkalinity, do not use copper
sulfate before consulting with a fisheries biologist.
Use a treatment rate of 0.5 ppm when
total alkalinity is between 20 and 50 ppm. Higher
treatment rates are needed in more alkaline water.
Use 1.0 ppm copper sulfate when alkalinity is between
50 and 100 ppm and 1.5 ppm copper sulfate
when alkalinity is between 100 and 150
ppm. Water of 150 to 200 ppm alkalinity needs
2 ppm copper sulfate. Copper sulfate is ineffective
in water of alkalinity greater than 200 ppm.
Potassium permanganate is commonly recommended
for treating some external bacterial and
parasitic diseases. It is an oxidizing agent that
reacts with organic matter in pond water. The
portion of chemical that reacts with organic matter
is ineffective in controlling disease.
As a rule of thumb, apply the recommended
rate of potassium permanganate and watch for
the water to change color. If the water turns
-15-
brown within 12 hours after treating, the full rate
must be applied again.
Ichthyopthirius, commonly called "Ich," is
probably the biggest killer of fingerling catfish.
"Ich" is a tiny parasite that burrows into the fish's
skin and gills, causing white, pin-head-sized spots
which can easily be seen. This disease is most
common in the spring when water temperature is
between 68°F and 77°F; however, it can appear
at any time of year. Treat "Ich" using 25 ppm
formalin ( 37 percent formaldehyde) every three
days when the water temperature is between 60° F
and 70°F, every seven days when the temperature
is between 50°F and 60°F and every 14 to 21 days
when the temperature is below 50°F.
Chemicals used for treating diseases should be
thoroughly mixed and evenly distributed from a
boat. Always wear protective clothing and follow
label instructions carefully.
Potassium permanganate, formalin and copper
sulfate kill algae in ponds, which may cause low
oxygen problems. Be sure to have emergency
aeration equipment readily available when treating
with these chemicals.
Channel catfish virus disease ( CCVD) is a
disease that affects only fry and fingerling channel
catfish when the water is warmer than 70°F. Signs
of this disease are pop-eye, hemorrhaging at the
base of the fins, swollen belly and pale gills. Behavior
includes erratic swimming and :floating
head-up. There is no cure for this disease, so prevention
is essential. Isolation of infected brood
stock is important because exposed adults are believed
to be carriers.
WATER QUALITY
Good water quality is essential to producing
healthy fingerlings. Low oxygen is by far the most
common water quality problem. Oxygen levels
should be above four ppm at all times for fingerlings
to grow well. Growth can be severely slowed
when oxygen remains below three ppm for long
periods. Stress caused by these conditions can
also lower resistance to disease.
Algae, the tiny plants that give water a green
color, produce oxygen during bright daylight and
put it into the water. However, no oxygen is produced
at night, and respiration of fish, algae and
decaying wastes take oxygen from the water.
When temperatures are high and fish are growing
rapidly, more oxygen may be taken out at night
than is being produced during the day. Also;
cloudy days may reduce the amount of oxygen
produced. The result can be dead fish. The probability
of low oxygen levels increases with higher

Figure 24. Test equipment: a) Dissolved oxygen chemical test kit.
b) Dissolved oxygen meter,
feeding and stocking rates. Dissolved oxygen
levels should be monitored daily at dawn and dusk
during warm weather. Oxygen test kits and more
expensive oxygen meters are commercially available
and are a worthwhile investment for the serious
producer (Figure 24). Records kept of daily
oxygen readings in each pond can help producers
predict low oxygen problems.
Emergency aeration equipment must be
readied when low oxygen is expected. Probably
the most effective device, especially for ponds
larger than two to three acres, is the tractor-driven
paddlewheel aerator. It quickly creates a zone of
oxygen-rich water where fingerlings concentrate.
The electric, surface-spray aerators are effective
for emergency use only in small ponds (Figure
25).
Some compounds found in water at relatively
small concentrations are potentially harmful to
fish. Copper and zinc are extremely toxic to fish.
Galvanized equipment such as pipes, containers,
-16-
screens and tanks may give up enough zinc to be
toxic. Copper from pipes and other eqmpment
can also be toxic to fish. Metal toxicity can be
particularly troublesome in the hatchery. Use
plastic pipe, buckets and other equipment wherever
possible.
Catfish are very sensitive to chlorine. Water
from city supplies must not be used in the hatchery,
to haul fish or to fill ponds unless it is dechlorinated
with sodium thiosulfate at 7 ppm for each
part per million chlorine. Most municipal water
supplies are chlorinated with less than 2 ppm.
Pesticides from cultivated watersheds may be a
problem in ponds that receive runoff. Some pesticides
are much more toxic to fish than others.
Prevent contamination of the water supply.
Harvesting and Handling
HARVESTING
Harvesting fingerlings is easier in ponds that
have clean, firm bottoms. Weeds and algae catch
in seines and make them difficult to pull. Fingerlings
also become entangled in the debris and are
injured. A mud-line should be used to prevent
the seine from digging into soft, mucky bottoms.
The mud-line also limits muddying the water
which stresses fish, especially during warm weather
(Figure 26).
About 75 percent of the fingerlings can be removed
by trapping them while they feed. Stretch
a 100- to 200-foot long seine parallel to shore at a
Figure 25. Aerators: a) Electrical spray-type surface aerator.
b) A paddlewheel aerator.

Table 7. LENGTH AND WEIGHT RELATIONSHIPS FOR VARIous
SIZE CHANNEL CATFISH FINGERLINGS.
Fish length
(inches)
1
2
3
4
5
6
7
8
9
10
Average weight
of 1,000 fish (lbs)
0.7
3.5
10
20
32
60
93
112
180
328
Number of
fish per pound
1500
286
100
50
31
17
11
9
5.5
3.1
and weighed. The weight of fish per thousand is
calculated from the sample. All the fingerlings
are weighed as they are loaded into the transporter
and the total number is estimated from
the average weight of the individual samples. For
example, two samples are taken of 200 fish each.
Sample weights are 10 ounces and 12 ounces. You
then have 22 ounces or 1.4 pounds per 400 fish,
or 3.5 pounds per 1,000 fish.
The total weight of all the fingerlings divided
by 3.5 pounds equals the total number in thousands
of fingerlings. From Table 7, the average
fingerling length is between three and four inches.
Unless the fish are uniformly graded, estimating
the average length from the table is unreliable.
HAULING
Fingerlings may be hauled long distances with
proper equipment and care. Use fresh, clean
water in the fish transporter. Hauling tanks
should be equipped with electric agitators to oxygenate
the water and to release waste gases such
as carbon dioxide and ammonia. Hauling tanks
should not be deeper than 30 inches when only
agitators are used. An air blower or bottled oxygen
is needed with deeper tanks or with exceptionally
heavy fish .loads. Bottled oxygen is also
a good backup in case the agitators fail (Figure
29).
Bottled oxygen is released into the water
through porous diffusers. Small bubbles transfer
more oxygen into the water than large bubbles. A
combination of small bubbles from bottled oxygen
and mechanical agitation achieves high oxygen
transfer and good waste gas removal, respectively.
The number of fingerlings that can be safely
hauled depends mainly on the volume of the transporter,
the efficiency of the aeration system, the
water temperature, the length of haul, and size
and condition of the fish. Hauling tanks should
be insulated to prevent water from over-heating,
particularly on long trips. Reduce the load given
Figure 29. Hauling tanks should always be equipped with bottled
oxygen in case other aeration systems fail.
Table 8. LoADING RATES FOR TRANSPORTING VARIOus SizE CATFISH
Fish size Transport time (hours)
(Number per pound) 8 hrs. 12 lm. 16 hrs.
- Loading rates (pounds fish/gal)
1 6.3 5.6 4.8
2 5.9 4.8 3.5
4 5.0 4.1 3.0
50 3.5 2.5 2.1
125 3.0 2.2 1.8
250 2.2 1.8 1.5
500 1.8 1.7 1.3
1000 1.3 1.0 0.7
10000 0.2 0.2 0.2
Rates given are for water temperature at 65°F and assume proper equipment and aeration. Reduce rates by 25 percent
for each 10°F rise in temperature.
-18-

Figure 23. Ship diseased fish in a plutic bag with oxygen and water
packed in a styrofoam container with ice to ensure survival.
The laboratory will infonn you of the diagnosis
and recommend a treatment if needed. Chemical
treatments are generally a last resort and are
recommended when there is no alternative. Table
3 contains chemical treatment recommendations
for common fish diseases. Take every precaution
when applying chemicals. Fish have narrow
tolerance ranges for some chemicals, so very
exact calculations are needed. Determine and
record the volume of all your ponds, tanks and
troughs for reference. Calculating treatment
rates is much faster when this information is readily
available.
Some characteristics of the water may affect
the treatment rates. Analyze your water before
you treat. Copper sulfate, for example, is toxic
to catfish in very soft water. When the water has
less than 20 ppm total alkalinity, do not use copper
sulfate before consulting with a fisheries biologist.
Use a treatment rate of 0.5 ppm when
total alkalinity is between 20 and 50 ppm. Higher
treatment rates are needed in more alkaline water.
Use 1.0 ppm copper sulfate when alkalinity is between
50 and 100 ppm and 1.5 ppm copper sulfate
when alkalinity is between 100 and 150
ppm. Water of 150 to 200 ppm alkalinity needs
2 ppm copper sulfate. Copper sulfate is ineffective
in water of alkalinity greater than 200 ppm.
Potassium permanganate is commonly recommended
for treating some external bacterial and
parasitic diseases. It is an oxidizing agent that
reacts with organic matter in pond water. The
portion of chemical that reacts with organic matter
is ineffective in controlling disease.
As a rule of thumb, apply the recommended
rate of potassium permanganate and watch for
the water to change color. If the water turns
-15-
brown within 12 hours after treating, the full rate
must be applied again.
Ichthyopthirius, commonly called "Ich," is
probably the biggest killer of fingerling catfish.
"Ich" is a tiny parasite that burrows into the fish's
skin and gills, causing white, pin-head-sized spots
which can easily be seen. This disease is most
common in the spring when water temperature is
between 68°F and 77°F; however, it can appear
at any time of year. Treat "Ich" using 25 ppm
formalin ( 37 percent formaldehyde) every three
days when the water temperature is between 60° F
and 70°F, every seven days when the temperature
is between 50°F and 60°F and every 14 to 21 days
when the temperature is below 50°F.
Chemicals used for treating diseases should be
thoroughly mixed and evenly distributed from a
boat. Always wear protective clothing and follow
label instructions carefully.
Potassium permanganate, formalin and copper
sulfate kill algae in ponds, which may cause low
oxygen problems. Be sure to have emergency
aeration equipment readily available when treating
with these chemicals.
Channel catfish virus disease ( CCVD) is a
disease that affects only fry and fingerling channel
catfish when the water is warmer than 70°F. Signs
of this disease are pop-eye, hemorrhaging at the
base of the fins, swollen belly and pale gills. Behavior
includes erratic swimming and :floating
head-up. There is no cure for this disease, so prevention
is essential. Isolation of infected brood
stock is important because exposed adults are believed
to be carriers.
WATER QUALITY
Good water quality is essential to producing
healthy fingerlings. Low oxygen is by far the most
common water quality problem. Oxygen levels
should be above four ppm at all times for fingerlings
to grow well. Growth can be severely slowed
when oxygen remains below three ppm for long
periods. Stress caused by these conditions can
also lower resistance to disease.
Algae, the tiny plants that give water a green
color, produce oxygen during bright daylight and
put it into the water. However, no oxygen is produced
at night, and respiration of fish, algae and
decaying wastes take oxygen from the water.
When temperatures are high and fish are growing
rapidly, more oxygen may be taken out at night
than is being produced during the day. Also;
cloudy days may reduce the amount of oxygen
produced. The result can be dead fish. The probability
of low oxygen levels increases with higher

DISEASES
Principal Diseases of Farm-Raised Catfish. J. A.
Plumb, editor. 1979. Southern Cooperative Series
No. 225. Alabama Agric. Exp. Sta., Auburn
University, AL.
Textbook of Fish Diseases. 1970. Erwin Amlacher.
T.F.H. Publications, Jersey City, NJ.
WATER QUALITY
Water Quality in Warmwater Fish Ponds. Claude
E. Boyd. 1979. Alabama Agric. Exp. Sta., Auburn
University, AL.
Water Quality Management in Pond Fish Culture.
Claude E. Boyd and Frank Lichtkoppler. 1979.
Alabama Agric. Exp. Sta., Auburn University,
AL.
NUTRITION
Nutrition and Feeding of Channel Catfish. R. R.
Stickney and R. T. Lovell, editors. 1977. Southern
Cooperative Series No. 218. Alabama Agric.
Exp. Sta., Auburn University, AL.
BREEDING
Genetics and Breeding of Channel Catfish. R. 0.
Smitherman, H. M. El-Ibiary and R. E. Reagan,
editors. 1978. Southern Cooperative Series No.
223. Alabama Agric. Exp. Sta., Auburn University,
AL.
Appendix 1
Selected References
-21-
GENERAL
Costs and Returns for Producing Catfish Fingerlings.
Robert E. Allain and W. R. Morrison.
1978. Bull. No. 831. Arkansas Agric. Exp. Sta.,
University of Arkansas, Fayetteville, AR.
Commercial Catfish Farming. Jasper S. Lee. 1981.
The Interstate Printers and Publishers, Danville,
IL.
Principles of \Varmwater Aquaculture. Robert R.
Stickey. 1979. John Wiley & Sons, Inc., New
York, NY.
Fish Farming Handbook. E. E. Brown and John
B. Gratzek. 1980. The A VI Publishing Co., Inc.,
Westport, CT.
Aquaculture; the Farming and Husbandry of
Freshwater and Marine Organisms. J. E. Bardach,
J. H. Ryther and W. 0. McLarney. 1972.
Wiley Interscience, New York, NY.
Fish Hatchery Management. Robert G. Piper, et.
al. 1982. U.S. Department of the Interior, Fish
and Wildlife Service, Washington, D.C.
Aquatic and Wetland Plants of Florida. 1978. Bureau
of Aquatic Plant Research and Control,
Florida Department of Natural Resources, Tallahassee,
FL.
Identification and Control of Weeds in Southern
Ponds. 1980. George W. Lewis and James F.
Miller. Cooperative Extension Service, The University
of Georgia, College of Agriculture,
Athens, GA.

Alabama Fish Farming Center
P.O. Box 487
Greensboro, AL 36744
( 205) 624-3651
Southeastern Cooperative Fish Disease Laboratory
Department of Fisheries and Allied Aquacultures
Auburn University, AL 36849
( 205) 826-4786
John K. Beadles, Ph.D.
Professor of Biology
Chairman, Division of Biological Sciences,
Arkansas State University, Jonesboro
State University, AR 72467
( 501) 972-3082
Dr. Roy Grizzell
Rt. 1, Box 496
Monticello, AR 71655
( 501) 367-8163
Scott Henderson, Fishery Biologist
Arkansas Game & Fish Commission
P.O. Box 178
Lonoke, AR 72086
(501) 676-7963
Andrew J. Mitchell
U.S. Fish & Wildlife Service
Fish Farming Experimental Station
P.O. Box 860
Stuttgart, AR 72160
( 501) 673-8761
Lanny R. Udey, Ph.D.
Department of Microbiology ( R138)
University of Miami School of Medicine
Fish and Shellfish Pathology Lab
(Exclusive of viral work)
P.O. Box 016960
Miami, FL 33101
( 305) 547-6563
University of Florida
J. Hillis Miller Health Center
Box J-136
Gainesville, FL 32611
( 904) 392-4777
Appendix 2
Fish Disease Diagnostic Laboratories
-22-
Jack L. Blue, D.V.M.
North Georgia Diagnostic Assistance Lab
College of Veterinary Medicine
University of Georgia
Athens, GA 30602
( 404) 542-5568
Department of Veterinary Microbiology
and Parasitology
School of Veterinary Medicine
Baton Rouge, LA 70803
( 504) 346-3306
Janice S. Hughes, Fisheries Biologist
Louisiana Wildlife and Fisheries Commission
P.O. Box 4004
Monroe, LA 71203
( 318) 343-4044
Tom Schwedler, Ph.D.
Area Extension Wildlife & Fisheries Specialist
Stoneville, MS 38776
( 601) 686-9311, Ext. 269
Thomas L. Wellborn, Jr., Ph.D., Leader
Extension Wildlife and Fisheries
P.O. Box 5405
Mississippi State, MS 39762
( 601) 325-3174
North Carolina State University
Department of Companion Animal &
Special Species Medicine
School of Veterinary Medicine
Raleigh, NC 27611
(919) 737-2910
University of Tennessee
College of Veterinary Medicine
P.O. Box 1071
Knoxville, TN 37901
( 615) 546-9230

The
-'.1Aiabama
W7Cooperative
Extension Service
AUBURN UNIVERSITY