Callichthyidae
    The fishes in this family are catfish with long plates on the flanks. By far the most popular catfish are those in the genus Corydoras. Most catfish are great scavengers and do a tremendous amount to keep the tank clean.
Mochokidae
    This is an interesting family of upside down catfish containing several species.
Cobitidae (Loaches and Botias)
    The fishes in this family are found in much of Asia and Europe, with a few in Africa. They are rather elongated in shape and live on or beneath the mud of pools. Mainly they are scavengers and can be very useful in an aquarium, seeking out scraps of food with the aid of their barbels. They have no teeth, but some species do possess sharp spines below the eyes. These spines are for protection and normally lie flat, but care should be taken when catching them as the spines tend to get caught up in the net. It is better to use a plain material net rather than a normal mesh net.