Red Fin Shark

About

The Red Fin Shark (Epalzeorhynchos munense) is a cyprinid from the river systems of Thailand, Laos, and Cambodia, including the Mekong and Chao Phraya basins. In the wild it favors boulder-strewn stream and river habitats, and during seasonal floods it ventures into inundated forest areas before retreating as water levels drop. Its appearance is genuinely distinctive: a largely black head, body, and anal fin contrasted with red dorsal and caudal fins and dark margins on the paired fins. Though this coloration is easily confused with related species like E. bicolor and E. frenatum, and potential hybridization between farm-raised fish means that positive identification can be tricky. Behaviorally, this species follows the typical pattern of the genus. Younger fish tend to stay hidden, but adults become increasingly territorial and can be relentlessly aggressive toward similar-looking species. Crossocheilus, Garra, and Gyrinocheilus tankmates are particularly at risk, while robust schooling cyprinids and certain loaches tend to fare better. Most keepers should house this fish alone, as each individual can require a large personal territory. It is rarely encountered in the hobby today, which makes it something of a curiosity. One for the dedicated intermediate keeper with a well-decorated, spacious tank.