Otocinclus Catfish

The Otocinclus Catfish (Otocinclus macrospilus), often called “Dwarf Suckermouth Catfish,” these tiny fish reach only 3.5 cm in length. They are easily identified by their sleek, peppered-grey bodies and a bold black stripe that ends in a distinct large spot at the base of the tail. They are native to the fast-moving rivers of the Amazon, they are built to cling to surfaces.

While you can have only one or two to clean a tank, the more the better. In the wild, they live in massive shoals, and keeping a large a group reduces stress. They thrive in a pH range of 6.0–7.5 and prefer well-oxygenated, stable water. Because they are sensitive to nitrates and sudden water changes, they are best added to aquariums that have been established for several months.They feed on algae, detritus, and biofilm.They will graze on surfaces like glass, rocks, and decorations, helping to keep the tank clean.

Otocinclus are arguably the most peaceful fish in the hobby, non-aggressive and won’t even bother baby shrimp. While they are scavengers it is important to supplement their diet with algae wafers, blanched zucchini, and  green beans to ensure they maintain their characteristic “plump” belly.