Loach is a group of small, slender, freshwater fish. Loaches live in mountain streams, lakes, and swamps in Europe, Asia, and Africa. There are more than 100 species (kinds) of loaches. Many loaches are flat on the underside, which allows them to lie on the bottom of fast-moving streams. Others have a rounder, more wormlike body. The mouth is on the underside of the head and is surrounded by three to six pairs of fleshy whiskerlike growths called barbels.
Most loaches are about 4 to 6 inches (10 to 15 centimeters) long. However, a species of loach called the European weatherfish can reach more than 18 inches (46 centimeters) in length. The weatherfish seems to become nervous and is much more active just before a thunderstorm. Scientists think the fish acts this way because it can sense the change in atmospheric pressure that precedes a storm. Some loaches, such as the clown loach, are colorful and popular aquarium fishes. Many loaches are delicious to eat.
