Zebra Oto

The zebra oto (Otocinclus cocama) is a distinctive small suckermouth catfish from the lower Ucayali and Marañón river basins in Peru, first described to science as recently as 2004. It reaches a maximum size of only 4–4.5 cm (1.6–1.8 in) and is named for its striking zebra-like vertical dark bars on a pale body — a pattern that makes it one of the most visually striking members of the genus. In the wild it inhabits small tributaries and slow-flowing marginal zones with dense aquatic vegetation and clear water.

This species is more delicate than the common Otocinclus macrospilus and must be added only to mature, well-established aquariums with a reliable supply of soft algae and biofilm, which form the bulk of its diet. A tank of at least 40 L (10 gal) with dense planting, floating vegetation, driftwood, and dried leaf litter is ideal. Water conditions should be stable: pH 6.0–7.5, temperature 21–25°C, with gentle filtration — an air-powered sponge filter is perfect. They are extremely sensitive to deteriorating water quality and should never be introduced to an immature tank.

Zebra otos are very peaceful, gregarious fish that must be kept in groups of at least six. They spend their daylight hours constantly grazing algae from plant leaves, wood, rocks, and tank walls. Supplement their diet with sinking algae wafers, spirulina-based foods, and blanched vegetables such as cucumber and zucchini. Without a consistent algae supply they will slowly starve, which is the most common cause of loss. Compatible tankmates include small, peaceful characins, Corydoras species, and dwarf shrimp. The IUCN lists O. cocama as Endangered due to its limited range and collection pressure for the ornamental trade.