Otocinclus

About

The otocinclus is a tiny armored suckermouth catfish prized as one of the few genuinely plant-safe algae eaters. Native to shallow, oxygen-rich South American streams, it clings to leaves, glass and wood while rasping soft green algae and biofilm. Gregarious by nature, it grazes in busy little herds and should never be kept alone. It is delicate on import and needs a mature, well-established aquarium.

Care

Keep 6+ in a mature, stable, well-oxygenated tank with established biofilm and algae. Sensitive to poor water quality and shipping stress; acclimate slowly and never rely on it to clean a new tank.

Diet

Herbivorous biofilm and soft-algae specialist; supplement with blanched vegetables and algae wafers. Will starve in a new or spotless tank.

Telling males from females

What works for this species, most reliable first.

• Bristles and cheek spinesStrong · from about a year

  Male plecos grow odontodes — spiny growths on the cheeks and along the leading pectoral rays. Bristlenose males additionally grow branching tentacles across the snout and over the top of the head.

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Frequently asked questions

What tank size does a Otocinclus need?

A Otocinclus needs an aquarium of at least 60 litres (15.9 US gallons) with a footprint at least 60 cm (23.6 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Otocinclus need?

Otocinclus does best at 21–27 °C (69.8–80.6 °F), pH 6–7.5 and a general hardness of 2–15 °dGH.

What group size does a Otocinclus need?

Otocinclus is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.

Is the Otocinclus suitable for beginners?

Otocinclus sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

• FishBase — Otocinclus vittatus
• Aquarium Co-Op — Otocinclus Catfish Care