Common Otocinclus
Otocinclus spp.
The Common Otocinclus (Otocinclus spp.) is a peaceful fish that's a good step up once you have a little experience. Give it a tank of at least 40 litres (11 US gallons), water held at 72-79°F, and a pH of 5.5-7.5. Always keep a group of at least 6 - they feel safest in numbers.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Rivers of south-eastern Brazil and the Paraguay basin.
- South America
Regional colours match the stocking calculator's origin map.
Common Otocinclus Tank Setup
Plan for at least 40 litres (11 US gallons) with soft sand or smooth, rounded gravel - sharp substrate wears down their delicate barbels. Keep the water at 72-79°F with a pH around 5.5-7.5. Always keep a group of at least 6 of their own kind - kept alone or in pairs they tend to turn shy, nippy, or wash out in colour.
What Do Common Otocinclus Eat?
They're grazers, so base their diet on algae, blanched vegetables, and spirulina-based foods rather than high-protein flake. A spotless tank with nothing to graze on leaves them thin and underfed.
Common Otocinclus Tank Mates
Sensitive to poor water quality; must be kept in groups; may starve in new or sterile tanks The Common Otocinclus is peaceful, which is the first thing to weigh up when you choose tank mates. It's a shoaling fish, so settle a group of 6 or more of its own kind before adding anything else - a stressed, lonely fish is far more likely to nip or hide. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Common Otocinclus Good for Beginners?
Doable once you test water regularly and catch problems before fish look sick. If this is your first tank, pick something more forgiving and come back later.
Common Otocinclus - frequently asked questions
What size tank do Common Otocinclus need?
Common Otocinclus need a tank of at least 40 litres (11 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
How many Common Otocinclus should I keep together?
Keep a group of at least 6. Common Otocinclus are a shoaling species and become stressed, lose their colour, or hide when kept singly or in pairs.
What water parameters do Common Otocinclus need?
Keep them at 72-79°F with a pH of 5.5-7.5, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Common Otocinclus eat?
Common Otocinclus are grazers. Base their diet on algae, blanched vegetables, and spirulina-based foods rather than high-protein flake. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Common Otocinclus good for beginners?
Common Otocinclus are best for keepers with a little experience. They are manageable once you test water regularly and catch problems early; a complete beginner may prefer something more forgiving first.
Common mistakes with Common Otocinclus
- Buying fewer than 6 - Common Otocincluss need a proper school to feel secure; isolated individuals hide, fail to colour up, or become stressed.
Guides that pair with this fish
- Otocinclus care guide - Acclimation, feeding, and groups.
- Best algae eaters - Compare crews before buying six otos alone.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Fish to avoid mixing with Common Otocinclus
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- Pea PufferPredator - Pea Puffer will eat or injure smaller tank mates
- Betta (Male)Predator - Betta (Male) will eat or injure smaller tank mates
