Select options Amazon Otocinclus (Otocinclus cf. macrospilus) – Group of 5 $14.99 One of the most popular aquarium algae eaters (and for good reason), the Oto Cat or Otocinclus is a small, schooling suckermouth catfish found throughout much of South America. There are several species commonly imported for the aquarium trade, but of these the larger, more robust species found in the Colombian Amazon (O. cf. macrospilus) is probably the hardiest and best choice for most aquariums. Safe for all planted tanks and compatible with any peaceful tankmates, the Amazon Oto will feed readily on diatom and other forms of nuisance algae in the aquarium but should be supplemented regularly with sinking veggie-based foods, gel diet, and fresh vegetables like zucchini or romaine lettuce.