Otocinclus

• ExerciseLow

  A calm, unhurried swimmer — peaceful surroundings suit them best.

• GroomingRoutine tank care

  Weekly partial water changes keep them in top shape.

• Living spaceNano-tank friendly

  Happy in a small, stable, well-filtered tank.

• Owner experienceSome experience helps

  A little know-how makes life smoother.

• Commitment3–5 years

  Plan for a long, loving relationship.

Health to watch: Ich (white spot) · Fin rot · Skin conditions

The otocinclus (Otocinclus spp.) is a tiny suckermouth catfish from the slow streams and river margins of South America, where it clings to plants and rocks grazing algae. It reaches only 4–5 cm and lives 3–5 years. Often called the 'dwarf sucker,' it is one of the best small, peaceful algae-eaters available. Otos are social and should be kept in groups of six or more in a mature, established tank of 40–75 litres at 22–27°C with a pH of 6.0–7.5. Crucially, they need a tank with a good growth of soft algae and biofilm, since they can starve in a brand-new or spotless aquarium. Provide plants, driftwood and gentle, well-oxygenated water. They are dedicated herbivores that graze soft green algae, biofilm and blanched vegetables like courgette; they must never be relied on to eat leftovers. Extremely peaceful and safe with shrimp and the smallest fish, they are sensitive to water changes and poor conditions. Their main risks are starvation in immature tanks and stress-related ich, both prevented by an established, algae-rich, stable tank.

• How active is a Otocinclus?

  Low. A calm, unhurried swimmer — peaceful surroundings suit them best.

• How much maintenance does a Otocinclus need?

  Routine tank care. Weekly partial water changes keep them in top shape.

• What tank size does a Otocinclus need?

  Nano-tank friendly. Happy in a small, stable, well-filtered tank.

• Is a Otocinclus a good fit for first-time owners?

  Some experience helps. A little know-how makes life smoother.

• How long do Otocinclus live?

  3–5 years. Plan for a long, loving relationship.

• What health issues affect the Otocinclus?

  Keep an eye out for Ich (white spot), Fin rot, Skin conditions. These are worth raising with your vet, along with any screening they recommend.

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