Maeklong Chameleon Catfish

About

Found in the cool, fast-flowing hill streams of Thailand's Mae Khlong drainage and Peninsular Malaysia's Pahang River system, this small akysid catfish, Acrochordonichthys septentrionalis, is one of the more unusual freshwater fish you're likely to encounter in the hobby. It belongs to the slender-bodied ischnosoma group within the genus, and its coloration is distinctive among relatives. A mostly pale cream body marked with just a few small brown spots, rather than the heavily mottled patterning seen in many of its cousins. That coloration can shift noticeably over time, because like other members of the genus, this fish periodically sheds its skin, appearing considerably paler immediately after molting. Perhaps the most important thing to know before setting up a tank for this species is its defensive capability: when stressed, it can secrete a milky substance through a pore near the base of the pectoral fin that is rapidly toxic to other fish in a closed system. For that reason, careful thought needs to go into tankmate selection. Smaller companions will simply be eaten, and any fish that might harass or stress this catfish becomes a genuine liability. Kept with appropriately sized, peaceful species that share a preference for cool, well-oxygenated water, a small group can be maintained without incident, since individuals tolerate each other provided no one is small enough to be swallowed.