Rhegma Catfish

Mystus rhegma is a seldom-exported bagrid catfish from the river systems of Myanmar, where it inhabits fast-to-moderate-flowing lowland and foothill rivers of the Irrawaddy drainage. It is distinguished from congeners by a bold, well-defined dark lateral stripe running from the snout to the base of the caudal fin. Its elongated body and long pectoral spines are typical of the genus, as is its strongly nocturnal lifestyle.

Virtually nothing has been published on its captive care specifically, but requirements can be inferred from closely related Mystus species. It will need clean, well-oxygenated water, moderate current, ample hiding places, and a diet of meaty foods. Given its moderate size (~35 cm), a 400-litre tank is the practical minimum for a single adult.

M. rhegma appears occasionally in European and North American import lists under generic 'Mystus sp.' designations and represents an exciting acquisition for the specialist collector seeking unusual Southeast Asian catfish. Proper identification and detailed notes on keeping conditions help build the knowledge base for this poorly studied species.

Water: 22–28°C, pH 6.5–7.5, moderate current; clean, well-oxygenated conditions. Tank: 400 L minimum; driftwood tangles and caves for refuge; low-light setup. Feeding: Live and frozen invertebrates, small fish portions, quality sinking pellets. Breeding: Undocumented in captivity; assumed similar to other Mystus pit-spawners. Compatibility: Semi-aggressive; avoid small fish; keep with similarly sized species.