Longhorn Cowfish

Lactoria cornuta is a variety of boxfish from the family Ostraciidae.

Description

It has long horns that protrude from the front of its head, rather like those of a cow or bull. It can grow up to 20 inches long.

There is no known sexual dimorphism, so both male and female display a yellow to olive base color, which is decorated with white or bluish spots.

One distinction from other fish is the lack of a gill cover, which is replaced by a small slit or hole. The hexagonal plate-like scales of these fish are fused together into a solid, triangular, box-like carapace, from which the fins and tail protrude.

Their unique method of swimming, called ostraciform swimming, causes them to look as if they are hovering. They have no pelvic skeleton, so they lack pelvic fins. They are such slow swimmers cowfish are easily caught by hand, making a grunting noise when captured. This is the most well-known cowfish species in the aquarium trade.

Distribution

Red Sea and East Africa eastward through Indonesia to Marquesas, northward to southern Japan. Including Tuamotus, southern Korea, north to the Ryukyu Islands of southern Japan, south to Australia and Lord Howe Island, and off southern Africa in the Atlantic. Tropical and subtropical waters.

Habitat

Its primary habitat is coral reefs in lagoons, on reef flats, and on protected seaward reefs. Juveniles associate with Acropora corals. Depth range is 3.3–148 ft (1–45 m).

Adults are reef fish, often solitary and territorial, and live around sand or rubble bottom up to a depth of 45 m. They are omnivorous, feeding upon benthic algae, various microorganisms, and foraminiferans that it strains from sediments, sponges, polychaete worms from sand flats, mollusks, small crustaceans, and small fishes, able to feed on benthic invertebrates by blowing jets of water into the sandy substrate.

Biology

Paired courtship just before or after sunset. Eggs and larvae are pelagic.

If severely stressed, this species may be able to exude deadly toxin, ostracitoxin, an ichthyotoxic, hemolytic, heat-stable, non-dialyzable, non-protein poison in the mucous secretions of their skin. It is apparently unique among known fish poisons; it is toxic to boxfish and resembles red tide and sea cucumber toxins in general properties.