Giant Sword Minnow

About

The giant sword minnow (Macrochirichthys macrochirus) is an impressive and unusual cyprinid from the major river systems of Southeast Asia, including the Mekong and Chao Phraya basins, where it inhabits large rivers and lakes at shallow to mid-water depths. During seasonal floods it pushes into submerged forest margins, retreating back to the main channel once water levels drop. It is the sole member of its genus and is immediately recognizable among Southeast Asian cyprinids by a notably upturned head, a nearly vertical mouth cleft, elongated pectoral fins, a sharp ventral keel running from the throat to the anus, and a distinctive dark blotch at the base of the tail. Lateral line scale counts of over 100 also set it apart. Adults are confirmed fish-eaters, while younger individuals focus on insects. Despite being listed as peaceful and even beginner-appropriate on paper, the reality is that this species grows very large, adults commonly exceed two feet, and is considered unsuitable for most home aquariums. Juveniles do occasionally appear in the trade. If you do keep one, tankmates should be of comparable size and non-aggressive, since it will consume anything small enough to swallow. The species has declined significantly across its range due to gillnet pressure and probable habitat degradation.