Lizard Loach

About

Found only in the hill streams of Sumatra, this small balitorid loach, Homalopterula gymnogaster, is one of six species in a genus restricted entirely to that island. H. gymnogaster itself originates from the Sumatera Barat province, where it inhabits fast-flowing, well-oxygenated streams. Like all members of the family Balitoridae, its body plan is purpose-built for life in rushing water: the paired fins splay out horizontally, the head and underside are flattened, and together these features create a suction-cup effect that lets the fish grip hard surfaces against strong current. Open-water swimming is largely replaced by a crawling, hopping movement across rocks and substrate that gives the whole group their informal nickname of lizard loaches. The belly is notably naked ahead of the pelvic fins, one of the key features that separates this species from its close relatives. Exact behavioral data is limited, but given what we know from related species, aggression toward tankmates is unlikely. In the wild these fish gather in groups, and keeping a half-dozen or more really brings out their natural behavior, including that characteristic habit of lining up side by side and facing directly into the current. A species for a well-maintained hillstream setup, and accessible enough for a careful beginner willing to research compatible tankmates.