Virginia Beck, age 13, of Williamsport, Penn., for her question:

HOW FAR UNDER WATER CAN FISH SWIM?

About two thirds of all fish live in the oceans of the world. This total adds up to about 14,000 species. Scientists have classified about 7,000 different kinds of fresh water fish.

The ocean fish are divided according to three levels of water depth.

Different fish swim to various levels._

Most of the world's fish swim only in the upper levels of water where the brightest of sunlight can be found. This water is no deeper than 600 feet.

Fish of the upper waters include such fast swimmers as the marlin and tuna and also the largest fish of the sea, including the manta ray.

In the midwaters, which go down to 3,000 feet and which has only 'e4im sunlight, you'll find many fish, including the bristlemouth, which outnumber all other kinds of fish.

There are not too many fish living in the black depths of the ocean below 3,000 feet.