Loaches are a kind of freshwater fish that are of the family Cobitidae. They are a small benthic fish having flattened ventral profiles, and there are about 160 different species. Loaches are chiefly scavengers, omnivorous, and usually are not very meticulous regarding their food. They might eat insects, aquatic crustaceans, other small invertebrates, and organic detritus’ scraps. Loaches mainly inhabit rapid moving streams, hence some of them adapt to less ideal water conditions and live in waters of poor quality, wherein they feed on tubifex worms found there.

The typical feature of the loaches is that the form of its body ranges from being vermiform or worm shaped to fusiform or spindle shaped. Most of its kind does not have true scales, but it has sensory organs called barbels. Loaches also have a small bottom facing mouth; below their eyes is an erectile spine; and a single chain of pharyngeal teeth.

Species of loaches are commonly found in Morocco and through Eurasia. The economic importance of some loaches is that they are known in East Asian nations as a fish eaten as food. Moreover, loaches are of significance in the fisheries and are being raised in aquaculture. Occasionally they are grown and used for bait. In addition, various kinds of brightly coloured loaches are known to the freshwater aquarist, thus playing a vital part in the aquarium trade. Moreover, the more colourful tropical loaches that are kept as pets are primarily from Southeast Asia and Southern Asia.