Zebra otocinclus
Otocinclus cocama
intermediate careOverview
The zebra otocinclus (Otocinclus cocama) is the most beautiful of the dwarf suckermouth catfishes — a 4–5 cm fish patterned with bold black-and-white zebra bands rather than the plain stripe of the common oto. Peaceful, sociable and endlessly busy grazing algae, it is a wonderful natural clean-up crew for a mature planted tank. Like all otos, though, it depends on a well-established aquarium to feed properly.
Tank & water
A group thrives in a mature, planted 45-litre (12-gallon) tank or larger with plenty of grazing surface.
- Temperature: 22–27 °C from a small heater.
- Water: soft to neutral, pH 6.0–7.5, clean, well-oxygenated and stable; otos are sensitive to poor water and nitrite. Test with a kit.
- Mature and planted: broad leaves, wood and glass coated in soft algae and biofilm are their feeding grounds.
- Gentle, oxygen-rich flow: a good filter keeps oxygen high, which they appreciate.
Feeding
Zebra otos are grazers on soft green and diatom algae and biofilm. A mature tank supplies much of their food, but always supplement with algae wafers, blanched courgette, cucumber and spinach, plus the occasional prepared sinking food. Watch their bellies — a hollow, sunken abdomen means they are underfed and need more supplementary food.
Behaviour & tankmates
Peaceful and shrimp-safe, zebra otos suit a calm planted community. They pair beautifully with small rasboras, tetras, cherry shrimp and pygmy corydoras. Avoid large, aggressive or fast, greedy fish that stress them or strip the algae they rely on. Keep them in a shoal for confidence.
Acclimatise new otos slowly, as they travel poorly and are sensitive to sudden changes in water; a gentle drip acclimation into a stable tank greatly improves survival. Once settled, a healthy group is remarkably long-lived and constantly at work over leaves, wood and glass.
Give the zebra otocinclus a mature, planted, well-oxygenated tank, a proper group and supplementary greens, and it is both a striking nano catfish and a tireless algae grazer — see how to plan stocking in how many fish in an aquarium.
Zebra otocinclus — frequently asked questions
Why do zebra otos need a mature tank?
Otocinclus graze soft green algae and biofilm, which only build up in an established aquarium. Added to a new, sterile tank they slowly starve, which is the main reason otos die. Wait until your tank has run for a few months with visible algae film before introducing a group.
How many zebra otocinclus should I keep?
Keep at least six, and more if the tank allows. The zebra oto is a social, shoaling catfish that is far bolder and more active in a group; kept singly or in pairs it hides constantly and does poorly. A larger group also spreads the grazing pressure.
Do zebra otos eat all types of algae?
Mostly soft green and brown (diatom) algae and biofilm — they will not clear tough black beard or hair algae. In a mature tank they graze well, but you must supplement with algae wafers and blanched vegetables, especially once they have grazed the tank down.
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