The hawkfish are tropical, perciform marine fishes of the family Cirrhitidae. Associated with the coral reefs of the western and eastern Atlantic and Indo-Pacific, they share many morphological features with the scorpionfish.
Hawkfish have large heads with thick, somewhat elongated bodies. Their dorsal fins are merged, with the first consisting of ten connected spines. Each spine has several trailing filaments on the tip. Their tail fins are rounded and truncated, and their pectoral fins are enlarged and scaleless. Their scales may be cycloid or ctenoid.
They are generally small, just about 7-15 cm in length. However, the largest of them, the giant hawkfish (Cirrhitus rivulatus) attains a length of 60 cm and a weight of 4 kg.
Vibrant colours of most of the hawkfish, easy upkeep acclimation to tank life have made it a popular choice for the aquarists, especially for fish only or FOWLR aquariums. Though they are not considered reef safe because of their propensity to eat small ornamental shrimps, they can be kept in reef tanks with extreme caution. Hawkfish can often be found resting in crevices of rocks or among the branches of corals or gorgonians due to lack of a swim bladder. Hawkfish are easy to care for and not at all fussy about water quality. A varied diet, including spirulina and small meaty foods like Mysis is recommended for them.
Some of the popular hawkfish are:
1) Long nose hawkfish (Oxycirrhites typus)
It is a red and pink coloured fish with crosshatch pattern on white body and as per its name; it has an elongated nose and tissue between the spines of the dorsal fin is missing.
2) Flame hawkfish (Neocirrhites armatus)
As the name suggests, it has striking red body with black fin tips and yellow lips.
3) Arc eye hawkfish (Paracirrhites arcatus)
It has brown to yellow body with reddish dorsal fin, distinctive white caudal fin, and small semicircular marking behind eye.
4) Spotted hawkfish (Cirrhitichthys aprinus)
It is bright red in colour with distinctive diamond shaped markings down back, becoming darker towards the topside of body.
Other varieties of hawkfish suitable for aquariums are Yellow hawkfish, White spot hawkfish, Red spotted hawkfish, Lyre tail hawkfish, Golden hawkfish, Freckled hawkfish, Falco’s hawkfish, Coral hawkfish and Blood red hawkfish.
Because of their large, skinless pectoral fins, hawkfish are able to perch upon fire corals without incurring harm. From here, they survey their surroundings like hawks. Hence, its common name.
Most hawkfish are solitary in nature, but some will form pairs and share a head of coral. Other species form harems of up to seven females dominated by a larger male. They are diurnal, and remain within the shallows of the reef, no deeper than 30 m. Typically motionless, hawkfish eat crustaceans and other small invertebrates which happen to pass by.
Spawning occurs at night, at or near the water’s surface. They release many tiny buoyant eggs, which drift with the ocean currents until hatching. That is why they are extensively distributed. Hatching takes place after about three weeks.
Hawkfish are noted for their protogynous hermaphrodism; that is functional females change into males if the dominant supermale dies. Hawkfish are generally not sexually dichromatic, meaning the sexes cannot be distinguished by coloration alone.