Otocinclus Catfish (Tank-Bred)

About

One of the most frequently traded members of its genus, Otocinclus macrospilus is a tiny Amazonian suckermouth catfish that turns up in stores far more often than hobbyists realize. Usually mislabeled as O. affinis or O. vittatus. It can be told apart from its near-identical relatives by the large, round black blotch at the base of the tail fin, a useful detail when you're squinting at a tank full of look-alike otos at the fish store. In the wild, the genus is spread across cis-Andean South America, typically living among marginal vegetation in small to medium rivers and streams. In the aquarium, this species is best described as intermediate care rather than beginner-friendly, mostly because freshly imported fish can be genuinely fragile. Almost all individuals in the trade are wild-caught, and they arrive stressed and often underfed. Adding them to a mature planted tank with stable water and a good crop of algae and biofilm makes a real difference to survival rates. Once settled, they're hardy and entertaining, often resting flat against the front glass. Keep a group of at least six, pair them with small peaceful tankmates, and watch for occasional quick dashes to the surface. This species can breathe air when conditions call for it, a neat adaptation shared across the genus.