Cowfish are a type of oceanic fish found at mid-sea level, about 50 meters (about 164 feet) deep. Their scientific name is Ostraciidae, although they may additionally be called trunkfish, boxfish, or cofferfish. As a member of the unique fish group Tetraodontiformes, this fish shares more similarities with pufferfish and sunfish than with other, more typical fish types. Notable features of this family of fish include bony skeletons, a box-like body, and hexagonal scales. Small fins and gills and several predator-defense methods are also associated with the cowfish.
A cowfish’s unique appearance readily distinguishes it from other types of fish. Bright colors and diverse patterns are characteristic of many tropical fish, and the cowfish are no exception. Unlike their counterparts, however, they are covered with six-sided hexagonal scales that give the appearance of a honeycomb. The aquatic animals also have a square-ish shape with a nearly vertical front end and a slightly triangular back. Protective scales often protrude from several species, making them difficult for predators to consume.
Other distinct features typify the cowfish. Due to their shape and small fins, most varieties move with a sluggish, rowing motion. Some types have horns attached to their heads for protection, no discernible gill covers, an ability to inflate, and can expel water from the mouth in a steady stream for sand displacement. Another defensive measure among a few species is the ability to emit poisonous substances known as ostracitoxin. Further, these fish have a skeleton made of bone, differentiating them from many kinds of fish that have skeletons made primarily of cartilage.
Around 25 species of cowfish are known to exist. One well-known variety is the longhorn cowfish, a reef-dwelling creature found mainly in the Indian and Eastern Pacific Oceans. Additional types range from the round-belly cowfish to the scrawled cowfish. Some of these types may reside in the open Atlantic Ocean. Others, however, may occasionally enter bays or harbors, preferring weeded, solitary areas where other marine life is scarce.
Most cowfish are omnivores, and feast on either smaller animals or plants along the reef line. A common diet could contain squid, shrimp, shellfish, and algae — and these can be fed to cowfish kept as pets. Additionally, if kept in a saltwater aquarium, the animals may attack smaller fish, either for food or for simple aggression.