Rick James, age 11, of Oak Hill, W. Va., for his question:

HOW MANY FISH SPECIES ARE THERE?

The list of known fishes includes about 21,000 different species, but this is not all. Every year, a few previously unknown species are discovered and identified. So gradually the list grows longer, and nobody knows for sure where it will end. However, the newly found species have places waiting for them in the system of scientific classifications.

About 30 species belong in the jawless group of lamprey type fishes. At least 600 species belong in the group of cartilage fishes, including the sharks and the rays.  The biggest group includes the bony fishes. There are at least 20,000 of them in the salt and fresh waters of the world. They come in a vast variety of shapes and colors, including many outlandish types. One of them is the tiny half inch goby ¬smallest fish in  the world.