Congo Killies - PageSuite

Killifish are associated with the ability to survive
in bodies of water that dry up periodically. The
development of the eggs extends over the dry
period, and the next generation hatches with the
next rainy season. The eggs can remain dormant
for many months, and not all the fry hatch in
the first rain; it might be not a downpour, but
just a brief cloudburst.
This ability is exhibited by the so-called annual
killifish. Typical annual genera include the East
African Nothobranchius and the South American
Austrolebias and Simpsonichthys, for example.
These genera unconditionally require a dry, dormant
period for the eggs, as otherwise they won’t develop.
But the majority of killifishes are not annual species.
Their eggs develop over a predictable period of
between 10 days and three or four weeks. So they don’t
absolutely need to be kept in a substrate such as peat or
chopped coconut hair to simulate a dry period in contact
with air, but can generally also develop in water.
Such species are termed “non-annual.”
There are also semi-annual killifishes, whose biotopes
dry up only occasionally. The eggs of these species
will develop both in water and in a substrate. The eggs
don’t stick to plants, so in this case, too, peat or something
similar should be used as a spawning substrate.
Aphyosemion are non-annual killies. The development
of the eggs takes around two to three weeks, with
temperature-induced variations up or down. If the
upper boundary of the time window is greatly exceeded,
the embryo will die while still in the egg or will be too
weak to break through the eggshell completely.
A pair of the recently described Aphyosemion pseudoelegans from
the vicinity of Boende, Tshuapa drainage.
Male Aphyosemion buytaerti BSW 99-03.
Continuous spawners
Aphyosemion are so-called continuous spawners. If the
fishes are in good condition and in the right mood,
they will lay a few eggs every day for a long period of
time. The number of eggs can vary from 0 to 20. If the
sexes are separated for several days beforehand, large
females may produce as many as 100 or more eggs
initially, but not infrequently the loss rate is very high if
there are a lot of eggs. The dead eggs fungus rapidly and
infect the good ones, and in the end you are left with
none. For this reason it isn’t especially desirable to get a
large number of eggs from a pair all at once.
A prerequisite for spawning is that the fishes should
be in good condition, and that is not least the result of
heavy feeding. The females should be visibly full of eggs.
They shouldn’t be full to bursting, but nothing can be
expected from noticeably slim individuals. It is usual to
offer live foods such as mosquito larvae or Cyclops. Lots
of fatty foods, such as Tubifex or White Worms, will
encourage egg formation. Some species will accept frozen
food, as long as they are accustomed to it.
It is always astonishing how rapidly the fishes react
to changes and improvements in feeding. If they have
M. SCHLÜTER
Aphyosemion herzogi from Zomoko GBG 92-25.
been fed sparingly for some time and haven’t spawned
much, or at all, you will often find significantly more
eggs a day or two after enriching the diet with a hefty
portion of live food.
Aphyosemion do not exhibit multifaceted courtship
behavior like many cichlids and gouramis. Instead, they
get right to the point. The male drives the female around
the aquarium and, when the opportunity arises, positions
himself in front of her and excitedly displays the
maximum possible splendor of coloration and finnage.
In some species the mouth area becomes as yellow as a
bright lemon as well—a pretty impressive sight.
If the female is willing to spawn, the pair press into
the spawning substrate together and she lays an egg. If
the female isn’t yet convinced, she is chased around the
tank time and again until she changes her mind. Should
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