Approximately 3,000 different species of catfish have been identified in the world, but they all share some common physical and behavioral traits.
Where Catfish Live
Catfish typically live in freshwater environments, usually closer to the coastal regions. They can be found on every continent on the planet, except Antarctica. Different catfish species tend to prefer certain types of waterways. For example, blue catfish are found mostly in large rivers, such as the Ohio and the Mississippi.
Most catfish have a broad but flattened head and recognizable barbels near their mouths. These barbels look similar to whiskers; however, they are actually home to the fish's taste buds. Even though these fish are named for these catlike whiskers, not all species of catfish have these barbells.
Catfish do have some physical differences. Depending on the species, catfish can be brown, black, yellow, white, tan or gray. They also can vary greatly in size. Some catfish species, such as the Aspredinidae, are capable of reproduction when they are only 1 centimeter in size while other catfish, such as the Mekong, have reached lengths of more than 9 feet.
A few catfish have unique body shapes. For example, the banjo catfish gets its common name from its wide head and thin body, which give it the appearance of a guitar or banjo. The banjo catfish also differs from other species because its body is covered by unculiferous tubercles instead of scales. The Candirus is another example. These South American catfish reach only 1 inch in length, have a suckerlike mouth, lack teeth on their lower jaw and have no scales. Instead, their bodies more closely resemble small eels.
Most catfish are carnivores. Different species prefer different prey, but catfish tend to be bottom dwellers who eat fish, worms and other creatures that stay in the same area. Some will eat amphibians, reptiles and mammals as part of their diet. The Candirus actually gets inside its prey, bites off part of the gills and eats the blood from the wound.
Most catfish are most active at night, and most prefer to live solitary existences instead of being part of a larger school of fish.
Before spawning, most species of catfish go through a period of courtship with their mates. This courtship causes the female to release eggs, which the male can fertilize. In some species of catfish, such as the blue and channel catfish, the male will guard the eggs until they hatch, which usually takes 6 to 10 days.