Species Spotlight: The Blacktip Grouper

Young Blacktip Grouper, Epinephelus fasciatus

By Daniel Knop with photographs by Werner Fiedler
from the January/February 2010 Issue of CORAL

Phylum: Chordata (chordate animals)
Class: Osteichthys (bony fishes)
Order: Perciformes (perch-like fishes)
Family: Epinephelidae (groupers)
Genus and species: Epinephelus fasciatus Forsskål, 1775

Here is a handsome species with immediate appeal to big-fish enthusiasts. With a maximum body length of 16 inches (40 cm), this species is one of the smaller groupers, and is immediately recognizable as such by its classic serranid physique.

The coloration varies greatly and depends on the substrate and the light conditions (depth). There are specimens with almost white flanks, and juveniles are more disposed to this. That apart, these fishes exhibit a dark reddish-brown banding on a lighter background of a similar color; this pattern can be more or less fragmented into spots. The distinctive dark red-brown patch on the head is typical; this “basket cap” extends from the mouth to the edge of the dorsal fin and includes the strikingly large eyes, although this color character is sometimes much paler. The tips of the hard-rayed section of the dorsal fin are black and have a white edge.

Distribution
The Blacktip Grouper occurs from the tropical part of the western Indian Ocean (East Africa, Red Sea) to the Pacific (Pitcairn Island). The division into two subspecies (Kuiter & Debelius 2007)—E. fasciatus from the Red Sea and Indian Ocean and E.  cruentatus from the southern western Pacific (including Indonesia)—has not yet been generally accepted.

Habitat
This common species inhabits reefs and rocky bottoms, lagoons, and drop-offs, from the shallow plateaus to a depth of 530 feet (160 m), preferring solid or pebbly areas. Sandy areas are apparently less to its liking, but it sometimes is found occupying corals surrounded by areas of sediment. It seems to prefer richly structured areas offering plenty of cover and sheltering caves.

Behavior
By day, the Blacktip Grouper spends most of its time resting, usually in a relatively open spot on the reef but sometimes hidden in a crevice or small cave. It remains almost motionless, propped up on its pectoral fins and camouflaged by its markings. But its eyes reveal that it is still very much on the alert; the fish keeps its surroundings under constant surveillance. The species shows little fear of divers.

Feeding
The Blacktip Grouper is predatory, preferring to feed on fishes and crustaceans, but doesn’t object to the occasional small octopus as well. Day and night, this fish lurks in wait for suitable prey. During the twilight periods it becomes somewhat more active and will then occasionally also pursue its prey.

Aquarium Maintenance
Obviously the Blacktip Grouper is not a suitable fish for a coral-reef aquarium with the usual type of population, as nothing that would serve as prey for this solitary fish can safely be housed with it. Aside from that, it is not particularly difficult to keep. However, because it can easily attain its maximum size in the aquarium, only a large tank with a volume of around 525 gallons (2,000 L) or more should be considered. The simulated reef landscape must provide appropriate hiding places, and the temperature should be 73.5–80.5°F (23–27°C), which is typical in tropical reef aquariums.

The food requirements of this hunter are relatively high. It goes without saying that live foods appropriate to its size are ideal, but this grouper can also be accustomed to pieces of fish, shrimps, mussel meat, Mysis, and coarse-grade frozen foods. During the transitional period it is helpful to offer the artificial food using forceps and move it to and fro to simulate living prey.

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References
Kuiter, R.H. and H. Debelius. 2007. Atlas der Meeresfische. Kosmos, Stuttgart, Germany.
On the Internet
www.fishbase.com
www.meerwasser-lexikon.de

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