THE STEINHART AQUARIUM - Gulf of Guinea Science ...

188 A Docent Field Guide to the Species of the Steinhart Aquarium
Remarks: Unicornfishes (Naso spp.) are
characterized by 2 sharp, fixed (not moveable
as in surgeonfishes), keel-like plates on the
caudal peduncle. The skin is leathery with tiny
non-overlapping scales, and teeth have finely
serrate edges.
Males of many Naso species are able to display
spectacular iridescent markings during courtship.
Orangespine Unicornfish
Naso lituratus (Acanthuridae)
Surgeonfishes, Tangs, and Unicornfishes
Distribution: Indo-Pacific.
Habitat: Over coral, rock or rubble of lagoon
and seaward reefs from the lower surge zone
to 90 m.
Appearance: Length to 46 cm. A hornless unicornfish,
despite the common name. Coloration
varies among populations. Ovate compressed
body typically black with yellow dorsal fin and
orange anal fin. Face white, prominent vertical
black stripe from eyes to mouth.
Diet: Primarily leafy brown algae.
Reproduction and Development: External fertilization,
open water pair spawning. Non-guarders.
Bluespine Unicornfish
Naso unicornis (Acanthuridae)
Surgeonfishes, Tangs and Unicornfishes
Distribution: Indo-Pacific.
Habitat: Inhabits channels, moats, lagoons and
seaward reefs with strong surge. Typically occurs
in small groups at depths of 1–80 m.
Appearance: Body color gray to olive , tail
spines blue, Short forehead horn does not
project past mouth. Adult males tend be larger
and have better developed horn, peduncular
spines, and caudal filaments than females.
Length to 70 cm.
Diet: Diurnal feeders on macro- and microalgae,
including brown algae like Sargassum.
Reproduction and Development: External
fertilization. Pair-spawning has been observed;
pelagic larvae.
Mortality/Longevity: An important food fish
on most tropical islands. Long-lived, up to 35
years. Preyed upon by other fishes.
Remarks: Rostral horn responsible for species’
common name.
Surgeonfishes have a single scalpel-like peduncular
spine which folds into a groove while
unicornfishes have 1 or 2 sharp, fixed keel-like
peduncular plates.
The spines are used both offensively and defensively.
Bignose Unicornfish aka Bumphead Naso
Naso vlamingii (Acanthuridae)
Surgeonfishes, Tangs and Unicornfishes
Distribution: Indo-Pacific.
Habitat: Deep lagoon and seaward reefs from
4–50 m.in conspecific groups off steep slopes.
Appearance: Length to 60 cm. Adults develop
a convexly rounded prominent snout and extremely
tall dorsal and anal fins. Gray ovate
compressed body with bright blue markings.
Tips of the tail fin are unusually long.
Diet: Zooplankton.
Reproduction and Development: External
fertilization. Egg scatterers, non-guarding.
Remarks: Courting males are able to
instantaneously turn iridescent blue.
Flagtail Surgeonfish aka Hepatus Tang
Paracanthurus hepatus (Acanthuridae)
Surgeonfishes, Tangs and Unicornfishes
Distribution: Indo-Pacific.
Habitat: Clear, current-swept terraces of seaward
reefs, 2–40 m. Typically in loose groups
1–3 m above substrate. Shelters among branches
of Pocillopora corals or in crevices of rocks.
Appearance: Ovate, compressed blue body. Tail
and pectoral fins yellow. Black oval extends under
dorsal fin to caudal peduncle. Length to 31 cm.
Diet: Zooplankton.
Reproduction and Development: Fertilization
external. Open water egg scatterers on
substrate. Nonguarders.
Remarks: Single scalpel-like peduncular spine
used offensively or defensively against conspecifics
in struggles for dominance or against
predators.
Dory, the co-star of Finding Nemo, with the
voice of Ellen DeGeneres’ “spaced-out” fish,
is a hepatus tang. Most kids now recognize
this fish as Dory.
Taken for commercial and aquarium trade.
Brown Scopas Tang
Zebrasoma scopas (Acanthuridae)
Surgeonfishes, Tangs, Unicornfishes
Distribution: Widespread throughout the