Robert Kitchen, age 8, of Saltsburg, Pennsylvania, for his question:

Which is the fastest fish in the sea?

Try to figure out how you would clock the speed of a fast fish. Underwater, he can swim ten times faster than a man. The job is not easy. You may try to keep pace with him from a boat. But you cannot ask the fish whether he is swimming at his top racing speed.

All sorts of animals live in the sea. The playful porpoises are not fishes, neither are the seals and the so called starfish. The true fishes are most at home in the sea and their streamlined bodies are built for swimming. The giant whale can swim at 25 miles an hour. So can the giant turtle and the frisky penguin, who happens to be a bird. These water loving, non fish animals can swim under water five times faster than a man can swim on the surface. But the fastest fish can leave them way, way behind. One fast fish has been clocked at 60 miles per hour.

It is not easy to clock the speed of a fish. In most cases, even the experts have to guess. We know that some kinds are faster than others. But when you check the speed of a fast fellow from a boat, you cannot be sure that he is doing his very best. However, it seems certain that the speediest fish are all big fellows. One of them is the whopping tuna fish who may weigh more than two big, fat men. He likes company and fishermen find him swimming along with a group of his big friends and relatives. The tuna never rests. He can dawdle along at nine miles an hour without ever getting tired. When in a hurry, he can speed up to about 45 miles per hour.

The big, silvery tarpon can swim almost as fast as the tuna. This fish is a giant cousin of the Epry little herring. The flying fish can spurt up to 40 miles an hour. This dainty creature is the fastest of the sea's small fishes. Another fast little fish is the silver blue mackerel. He likes company and he never stops swimming, day or night. The mackerel is a small cousin of the huge, speedy tuna. And the pride of his family is the whopping sailfish    who happens to be the world's champion swimmer.

The magnificent sailfish may be 11 feet long and tip the scales at 220 pounds. His scaly skin is a glistening blend of silver and midnight blue. His nose tapers to a long, sharp spike and he gets his name from the oversized fin on his back. It sticks straight up like a stiff, silvery blue sail. Sportsmen hunt him down in special boats and it takes a clever fisherman to land him. The sailfish is strong and he fights hard for his life. He darts and dodges and leaps right out of the water to free him¬self from the line. At his top speed, the magnificent giant fish can reach 60 miles an hour.

The marlin and the wahoo are big game fishes that belong to the sailfish family. They, too, are powerful creatures and they too fight fiercely for their lives. The wahoo and the marlins are also fast. A few of them have been clocked for speed and some fishermen claim that they are as fast as the champion sailfish. Some experts claim that the wahoo may be even faster. But at present we do not have enough reli¬able records to be certain.