The Longhorn Cowfish (Lactoria cornuta) is a species of boxfish that is a resident of the Indo-Pacific region. They are found from the Red Sea and East Africa eastward through Indonesia to Marquesas, and northward to southern Japan. They are also found as far south as Australia and off southern Africa in the Atlantic. Adults are mainly solitary and territorial and live around coral reefs in lagoons, on reef flats, and on protected seaward reefs and in sand or rubble bottom up to a depth of 165 feet.
Adults are 4 inches long and they have two horns that protrude from the forehead. Both male and female display a yellow/olive base color that is decorated with white or bluish spots. They have a unique method of swimming which makes them look more like they are hovering than actual swimming. They have no pelvic skeleton, so they lack pelvic fins. They are such slow swimmers that they can actually be caught by hand. They make a grunting noise when captured.
They feed upon benthic algae, various microorganisms, and foraminifera 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.
If severely stressed, this species may be able to exude deadly toxins or 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.