Smokey Glass Catfish

About

Sometimes sold under the trade name 'smokey glass catfish', this transparent Southeast Asian catfish, Kryptopterus cryptopterus, is native to the Malay Peninsula, Java, Sumatra, and Borneo, where it inhabits rivers and seasonally flooded areas. It belongs to a closely related pair of species alongside K. geminus. Populations of the latter were long misidentified as K. cryptopterus, which explains some of the confusion around this fish in the hobby. The two can be told apart by head width, snout length, and the placement of the eyes, though for most hobbyists the distinction is academic. In the aquarium, this is a peaceful, somewhat shy catfish that genuinely needs the company of its own kind. A group of four or more will settle in far better than a lone specimen and will form loose schools in open water. That said, it can make a meal of very small tankmates, so nano fish are best avoided. It holds its own best with peaceful, similarly sized cyprinids, loaches, and other catfishes rather than boisterous or larger species that might stress it out. Breeding has not been documented in captivity. Despite its size and carnivorous diet, it is generally considered manageable for hobbyists without years of experience.