Otocinclus Catfish

About an Inch to 1.5”

Otocinclus Catfish — Quick Care Guide

✔ Species Overview

• Common names: Oto, Dwarf Sucker, Otocinclus

• Size: 1–2 inches (2.5–5 cm)

• Lifespan: ~3–5 years

• Temperament: Peaceful, shy

• Role: Excellent algae eaters (especially soft green algae)

✔ Tank Requirements

• Tank size: Minimum 10 gallons (bigger is better)

• Group size: At least 6+ — they are highly social

• Water flow: Gentle to moderate

• Substrate/Decor: Plants, driftwood, smooth surfaces to graze on

✔ Water Parameters

• Temperature: 72–79°F (22–26°C)

• pH: 6.5–7.5

• GH: 6–15 dGH

• Ammonia/Nitrites: 0

• Nitrates: <20 ppm

• Stability: Critical — sensitive to sudden changes

✔ Diet

• Primary: Naturally occurring algae (green film, soft diatoms)

• Supplement with:

  • Blanched zucchini/cucumber

  • Algae wafers

  • Spirulina tablets

• Feeding tip: Their stomachs are small; frequent grazing matters more than large feedings.

✔ Tankmates

• Perfect with:

  • Small tetras

  • Corydoras

  • Shrimp

  • Rasboras

  • Peaceful nano fish

• Avoid:

  • Aggressive fish

  • Big fish that might eat them

  • Fast, pushy feeders that outcompete them

✔ Common Issues

• Starvation: Most common cause of death; ensure algae & supplemental food

• New tank syndrome: They struggle in immature tanks

• Stress: Needs groups + hiding spots

• Medication sensitivity: Avoid copper-based meds

✔ Best Tips for Success

• Add them only to established tanks with visible algae

• Keep in large groups

• Offer veggie foods regularly

• Maintain clean, stable water

• Provide lots of plants and calm areas