Loaches: Playful Diggers That Need Soft Sand

Busy Bottom Dwellers

Loaches are an active, diverse group from Asia, and OATA notes most in the trade are captive bred and easy-going. Popular species include the clown loach, the kuhli loach and the zebra loach. Many are peaceful, playful fish that bring life to the lower part of the tank.

Groups and Sizes

Loaches are social: OATA recommends groups of at least five, as lone loaches are often stressed. Most stay under 4 inches (10 cm), but the clown loach can grow over 12 inches (30 cm) and needs a very large tank from the start; OATA suggests one over 6 feet (1.8 m) long for adults.

Loaches have a sharp spine under each eye, so handle and net them carefully.

Tank, Sand and Water

OATA recommends at least about 21 gallons (80 liters) for a shoal of the smallest species.

• Substrate: fine gravel or, ideally, sand, to protect their sensitive skin and barbels when they dig and burrow.
• Cover: plants, caves and wood, plus open space to swim.
• Temperature: about 72–81°F (22–27°C).
• Water: pH about 6.5–8.0, soft to medium hardness, gentle flow for small species.
• Lid: kuhli loaches can squeeze through small gaps.

Feeding Loaches

OATA suggests good-quality sinking pellets or granules, plus small live or frozen foods such as daphnia and bloodworm. Some species eat snails and are kept for pest control. Feed in the evening for shy, nocturnal species like kuhlis.

Tank Mates

Loaches mix with most community fish, but their activity can bother shy species, so OATA suggests confident tank mates such as danios, larger tetras or barbs. Some species, including the red-tailed botia and skunk loach, can be aggressive and need larger, robust tank mates.

Keeping Them Healthy

Most problems in small fish start with water quality. Test ammonia, nitrite and nitrate weekly, change about a quarter of the water each week with conditioned tap water, and rinse filter media in old tank water, never under the tap. Quarantine new fish if you can, and add them a few at a time so the filter keeps up.

Watch your fish every day at feeding time. Changes in swimming, color, breathing or hiding are early signs that something is wrong, so test the water first.

For fish treatments or medicines: see your vet or a pet supply store with trained staff. An aquatics store with trained staff, or a vet who treats fish, can help you work out what's wrong before you add anything to the tank.