Stone Loach

Adult Stone Loach reach about 10–12 cm in length. The body is elongated and slender, with a relatively large head. The fins are rounded and slightly jagged at the edges. Three pairs of barbels near the mouth serve a sensory function. Coloration is yellowish-brown, patterned with dark spots and speckles of irregular shape. Sexual dimorphism is weak; males and females are virtually indistinguishable.

The Stone Loach is widespread in Europe and parts of Asia, inhabiting rivers, streams and lakes with clean, well-aerated water. It prefers areas with stony, pebbly or sandy substrate and lives near the bottom, often burrowing into the sediment. In nature it occupies waters with moderate to fast flow, avoiding stagnant, heavily polluted or brackish water.

In spacious tanks the Stone Loach coexists well with its own kind and with other fish of comparable size. By nature it leads a secretive life; in the presence of overly active or unfriendly fish, it will withdraw further. Good tank mates include other river fish, as well as goldfish and koi.

A tank for 3–4 individuals should hold at least 100 litres. When decorating, provide shelter with large stones and driftwood. Plants are not essential. Similar conditions suit the species in a pond. The Stone Loach is most comfortable in slightly alkaline or neutral water of moderate hardness, at temperatures not exceeding 23 °C. Care is similar to that for tropical fish: perform a partial water change each week and remove organic waste (uneaten food, faeces), usually combined with siphoning the substrate. Service equipment according to the manufacturer's instructions.

The Stone Loach adapts well to alternative feeds such as sinking flakes and pellets. Feed in the evening, shortly before lights out, as this species is most active at dusk.

Spawning occurs in spring and summer, from April to August, depending on climate and water productivity. Females lay eggs in batches on a substrate of stones, gravel or among aquatic plants. In captivity, breeding is difficult and requires simulating natural conditions: creating water flow, maintaining high oxygen levels and using fine-grained substrate to mimic spawning habitat.

The species is sensitive to water quality, especially oxygen content and heavy metals. Under poor conditions the fish are prone to stress, shown by dark bands on the body. The Stone Loach may serve as an intermediate host for various parasitic worms, including nematodes, and can be an asymptomatic carrier of viral diseases affecting cyprinids. Prevention relies on maintaining clean conditions and regular water changes.

When purchasing, choose active individuals without visible skin damage, ulcers or signs of emaciation. A healthy fish should display natural behaviour, actively exploring the bottom with its barbels, and show no signs of lethargy or unnaturally dark coloration indicating stress. Avoid specimens with cloudy eyes or damaged fins. Ask the shop about the holding conditions, as this species is sensitive to temperature.