Otocinclus

Otocinclus vittatus

Also known as: Oto, Dwarf sucker, Otto cat

Water Parameters

• Temperature: 21–25°C
• pH: 6–7.5
• Hardness: 36–179 ppm

Care Summary

A tiny, peaceful algae-eater often marketed as a beginner fish — wrongly. Otocinclus require a mature tank rich in biofilm and soft green algae as their primary food. New tanks lack the biofilm they need, and most otos sold are wild-caught and arrive starved and stressed, leading to high early mortality. Once acclimated to a stable, established tank, they're hardy and long-lived. Supplement their diet with blanched zucchini and proper algae wafers. Often considered a more peaceful and tank-safe alternative to bristlenose plecos for smaller setups.

Tankmates

A peaceful schooling algae-eater best kept in groups of at least 6. Solitary or paired otos become stressed and stop feeding. Compatible with most peaceful community species. Often sold individually by pet shops despite being a schooling fish — buying just one or two is the most common mistake new keepers make. Requires an established, mature tank with biofilm and soft algae; will starve in a new or pristine tank regardless of supplemental feeding.

Compatible with

• Neon Tetra
• Harlequin Rasbora
• Ember Tetra
• Cherry Shrimp
• Bronze Corydoras
• Mystery Snail
• Honey Gourami

Avoid keeping with

• Betta
• Large Cichlids
• Fin Nippers
• Aggressive Tankmates

Common Problems

• starvation in new or under-fed tanks
• wild-caught stress and parasites on arrival
• sensitivity to copper and medications
• drops in health when kept singly

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-03