Otocinclus
Otocinclus vittatus
Animalia›Chordata›Actinopterygii›Siluriformes›Loricariidae
📍 Venezuela to Argentina, South America
The otocinclus, or 'oto cat', is a diminutive algae-eating catfish prized for keeping plant leaves spotless without disturbing the aquascape. It requires a mature, well-established tank with existing algae film as a primary food source. Keep in groups of five or more as they are social fish that suffer in isolation.
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Tanks keeping this 🐟
Kept by 11 hobbyistsCommunity tanks featuring Otocinclus.
Care Guide
Diet
Otocinclus are primarily herbivorous and rely heavily on algae film and biofilm naturally present in established tanks. Supplement with blanched vegetables (zucchini, cucumber), spirulina wafers, and high-quality algae-based pellets 2-3 times weekly. Feed small amounts that are consumed within a few hours to prevent water quality issues.
Behavior
These are highly social, peaceful bottom-dwellers that spend most of their time grazing on surfaces and plants. They are nocturnal and most active during dawn and dusk, often hiding during bright daylight. Otos are sensitive to water conditions and tank disturbances, so they require calm, stable environments with plenty of hiding spots.
Breeding
Breeding in captivity is extremely rare and difficult, with few documented successes in home aquariums. They require very specific water conditions, mature biofilm, and stable parameters to even attempt spawning. Most specimens in the hobby are wild-caught, making captive breeding impractical for most hobbyists.
Tank Mates
Similar size, peaceful temperament, and identical water parameter requirements make them ideal companions
Peaceful schooling fish with overlapping temperature and pH ranges; non-aggressive toward bottom-dwellers
Both are algae-eaters that occupy different feeding niches; compatible water parameters
Peaceful mid-water dweller that won't compete for bottom space or harass small otos
Small, peaceful invertebrates that share similar water conditions; minimal competition
Generally peaceful but may occasionally investigate or stress small otos; requires careful observation
Common Diseases
Ich (White Spot Disease)
White spots on body and fins, rapid gill movement, lethargy, rubbing against surfaces
Raise temperature gradually to 28-29°C, perform daily 25% water changes, use quality ich medication; otos are sensitive to salt, so avoid salt-based treatments
Bacterial Infection
Torn fins, cloudy eyes, sores on body, loss of appetite, color fading
Perform frequent water changes, improve water quality, use broad-spectrum antibiotic medication if severe; maintain pristine tank conditions
Malnutrition/Starvation
Extreme thinness, sunken belly, lethargy, inability to cling to surfaces
Ensure tank has adequate algae film by reducing water changes temporarily; supplement with quality algae wafers and blanched vegetables daily
Gill Flukes
Rapid gill movement, gasping at surface, rubbing gills, lethargy
Use anti-parasitic medication designed for sensitive fish; perform daily water changes; improve water circulation and oxygenation
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Quick Facts
- diet
- Herbivore – algae film, blanched zucchini, spirulina wafers
- lifespan
- 3–5 years
- max size
- 4 cm (1.6 in)
- tank size
- 10 gallons minimum
- school size
- 5+
- temperament
- Peaceful
Water it likes
- ph
- 6.0–7.5
- ammonia
- 0 ppm
- nitrate
- <10 ppm
- hardness
- 3–15 dGH
- temperature
- 70–81°F (21–27°C)