Hillstream Loach ~ Sewellia lineolata

The Hillstream Loach, also known as the Butterfly Loach or Reticulated Hillstream Loach, is a peaceful freshwater fish renowned for its unique, flattened body and intricate patterns. Adapted to fast-moving rivers in Southeast Asia, this hardy species thrives in well-oxygenated aquariums with high water flow, where it helps control algae while providing an eye-catching addition to aquascapes.

• Size: 2-3 inches
• Lifespan: 5-8 years
• Temperament: Peaceful, social
• Group/Solitary: Best kept in groups of 3+
• Food: Omnivorous; biofilm, algae wafers, blanched vegetables, live/frozen foods (bloodworms, daphnia)
• Water Requirements: 68-75°F, pH 6.5-7.5, soft to moderately hard water, strong water flow

Hillstream Loaches are native to the fast-flowing, shallow rivers and streams of Vietnam and other parts of Southeast Asia. These habitats are characterized by cool, highly oxygenated water, rocky substrates, and a steady current, all of which the loaches are perfectly adapted to. Their flattened bodies and suction-like fins allow them to cling to smooth surfaces, resisting the powerful flow of their native waters. In aquariums, this species thrives in setups that replicate these conditions, including strong water flow from powerheads or filters, clean water with high oxygen levels, and smooth rocks or driftwood for grazing. Their diet primarily consists of biofilm and algae, though they benefit from supplemental foods like sinking algae wafers, blanched vegetables such as zucchini or spinach, and occasional live or frozen treats like daphnia or bloodworms.

Hillstream Loaches are social fish that do best in small groups, where their natural behaviors can be observed. They are peaceful tankmates and can be housed with other cool-water, non-aggressive fish, such as danios, White Cloud Mountain Minnows, or shrimp species. With proper care and a suitable environment, these loaches are hardy, long-lived additions to freshwater aquariums.

Fun Fact: The Hillstream Loach’s flattened body and suction-like fins are specialized adaptations that allow it to "cling" to rocks and surfaces in fast-moving rivers, enabling it to resist strong currents while foraging for food. This unique feature also makes it an excellent algae grazer in aquariums.