John Conerty, age 10, of Indianapolis, Indiana, for his question:

Is there such a thing as a walking fish?

This sounds like a wondrous dream from Alice In Wonderland, a fabulous book that mentions a crocodile who weeps tears of phony sympathy and a talkative cat who disappears by magic, allowing his smile to linger until last. Alice did not meet any walking fish, but in the real world such things do indeed exist.

The earths 30,000 species of fish have gills to extract dissolved oxygen from the water and naturally the vast assortment of land animals have lungs to extract their needed oxygen from the air. As a general rule, creatures with lungs are limited to living on the dry land and those with gills are supposed to stay under water. But nothing in the world of nature is downright impossible, or so it seems. Even the most hard and fast rules are broken    sometimes.

For example, an adult frog has air breathing lungs. But he can squat for hours under water on the bottom of his pond    because he absorbs oxygen through his amazing amphibian skin. And a few of the fishes have ways to survive out of water for long periods of time. Obviously a fish must be able to do this if he plans to do any success¬ful walking on the dry or fairly dry land.

One of the most inventive groups is the catfish clan of mote than 2,000 species. All of them wear fleshy whiskers called barbels on their noses, which serve as feelers. Some wear scales and some do not, some live in fresh water and some prefer the sea. They range in size from one inch to a ten foot giant that weighs 400 pounds. There are armored catfishes, upside down catfishes and electric catfishes. There is a so called talking catfish    so nobody should be surprised to learn of a walking catfish.

The walking catfish is a native of India and other parts of Asia where the rainfall is undependable. Through half the year, the seasonal monsoon winds drench the ponds and streams. Then the winds reverse the dry monsoon season takes its toll of moisture from the land. This is when the walking catfish does his walking.

It so happens that, in addition to his gills, this remarkable fish has special air breathing organs that serve as lungs. The average walking catfish has a wide head and a round nose, two small sturdy fins on his shoulders and a long tapering body. When his stream begins to dry up, he comes on land to find a source of deeper water. He progresses by using his shoulder fins as supporting legs and pushes forward by humping and straightening his body.

Some years ago, these Asian walking catfish were imported and careless people allowed them to escape into Florida's inland waters. They multiplied at a great rate and ferociously attacked the more desirable native fishes. This unwelcome catfish can leave the water and keep walking for twelve hours, most likely in search of less crowded streams in which to multiply.