Loaches are bottom-dwellers who make excellent scavengers. They spend their days searching the tank's floor in search of uneaten food, helping to keep the tank clean. They add beauty to the tank, as they come in a wide range of colors. They also come in a variety of sizes, so choose the loach that best fits the size of tank you have.
Clown loaches, one of the most popular varieties, are schooling fish that need to be kept in groups of at least six of the same species. If you do not keep a nice school of these fish, they will become aggressive. Most loaches can grow quite large, so you need at least 30 gallons for these fish. Loaches have an interesting habit of "playing dead" by remaining incredibly still and laying on their sides on the tank bottom. Do not assume the fish is dead unless it is floating.
Loaches do not tolerate poor water quality, so make sure your tank has excellent filtration, do regular water quality checks, and clean the tank regularly. Keep lighting subdued, as these fish are nocturnal and will not come out in highly lit tanks. Use only fine-grain gravel as your substrate, so that the fish do not injure themselves on the substrate.
Loaches are highly prone to ich. Watch carefully for this condition, and treat the entire tank the moment you spot a problem. These fish do best in water that is slightly acid or slightly alkaline with a pH between 6.5 and 7.5. Water for these fish should be slightly hard.
Consider including sinking pellets in the food you give your fish to ensure the loaches have something to feed on. Supplement live foods like bloodworms and brine shrimp to the tank to keep your loaches as healthy as possible.