Flat loaches are a captivating group of freshwater fish known for their distinctive appearance and engaging behaviors. Their unique flattened body shape and intricate patterns make them a visually appealing addition to many home aquariums. These bottom-dwellers offer a unique glimpse into aquatic life.
Characteristics and Natural Habitat
Flat loaches, often called Hillstream Loaches, include species like the Reticulated Hillstream Loach (Sewellia lineolata) and the Butterfly Hillstream Loach (Beaufortia kweichowensis). These fish reach 2 to 3 inches, with Sewellia lineolata growing to about 2.5 inches (6.4 cm). They have a flattened body and wide, horizontally oriented pectoral and pelvic fins, allowing them to firmly adhere to surfaces, resembling a miniature stingray.
Their coloration varies, often featuring intricate patterns of lines, spots, or reticulated designs across their streamlined bodies. These loaches originate from fast-flowing streams and rivers across Southeast Asia, including China, Vietnam, Laos, Cambodia, and Borneo. Their natural environments feature strong currents, clear, oxygen-rich water, and rocky substrates. They are found clinging to rocks in shallow riffles, river rapids, and calmer stream pools, where they graze on algae and other microscopic organisms.
Care in a Home Aquarium
Replicating their natural environment benefits flat loaches in a home aquarium. A minimum tank size of 20 gallons is suitable. While traditionally thought to require strong currents and cool temperatures, they show adaptability and can thrive in various setups, including warmer tanks or those with more gentle filtration, provided water quality and oxygenation are maintained.
Water parameters should be stable, with a temperature range between 68-78°F (20-26°C) and a pH between 6.5 and 7.5. High oxygenation is recommended, achievable through strong filtration or air stones. The substrate should include smooth rocks, pebbles, and driftwood, offering ample surfaces for grazing and hiding spots.
Flat loaches are primarily herbivorous, naturally scraping algae from surfaces. In captivity, their diet should be supplemented with high-quality foods such as sinking algae wafers, spirulina flakes, blanched vegetables like zucchini or cucumber, and small frozen foods like brine shrimp or bloodworms. They are peaceful and can coexist with other community fish that prefer similar water conditions. Ensure tank mates are not aggressive or large enough to pose a threat. A tight-fitting lid is recommended, as these loaches can sometimes climb out of the aquarium.