Jeannine Hinshaw, age 13, of Billings, Mont., for her question:
HOW MANY KINDS OF CATFISH ARE THERE?
Catfish is a name given to a large group of fish, most of which have two to four pairs of cat like whiskers. There are more than 2. 000 species of catfish.
Many of the catfish have sharp spines on their back fins and on the fins near their gills. The spines in some of the species give off a poison when they pierce another animal.
Unlike most other fish, catfish have no scales over their skin.
Especially remarkable is the walking catfish of tropical Asia. It can actually move overland to another body of water if its pond dries up.
This fish pushes itself along the ground with its tail, using its strong front fins to lift the front part of its body. The walking catfish has gills, but it also has lunglike breathing organs. These organs enable the fish to stay out of the water for days if the surroundings are wet or rainy.
Even in dry conditions the walking catfish can survive out of water as long as 12 hours. This fish can also now be found in some rivers in southern Florida. The fish has actually replaced other kinds of fish in some Florida waters.
Many people consider the catfish to be a delicious food item. Channel catfish, blue catfish and yellow catfish are each a fisherman's prize in the Mississippi River Valley. The bullhead, a type of catfish, is also a popular food dish in the eastern United States.
A number of catfish farms, most of them in the Southern states, raise channel catfish for use as food.
Smallest of the catfish is the pygmy corydoras. It is only one inch long and weighs about one tenth of on ounce. Largest species, the European catfish, may grow to be more than 10 feet long and weigh 400 pounds.
Catfish are found in most parts of the world. Some live in fresh water and others in salt water.
Most species of catfish live in fresh water that is quiet. They ususlly feed on tiny animals and bits of animal flesh. They find their food near the bottom of a pond or a slow moving river.
A few species of catfish live in swift streams. They include the channel catfish, which lives in North America. Such catfish eat othe fish, frogs, crayfish and insects.
The armored catfish has overlapping bony plates that cover its body.
The electric catfish can send out a strong electric shock.
The eel cat, a West African catfish, is so long and slim that it resembles an eel.
The candiru, a Small South American catfish, swims into the gills of larger fish. It then rips the gills with its sharp spines and drinks the victim's blood.
Among some species of ocean catfish, the male carries the eggs in his mouth and then does not eat any food. He holds the eggs in his mouth until they hatch.
Many people keep small catfish, called glass catfish, in their home aquariums.