Otocinclus

Is Otocinclus a good aquarium fish?

Otocinclus reaches about 4 cm as an adult, so plan around the adult fish rather than the juvenile size seen in shops. The suggested minimum of 20 US gallons assumes suitable filtration, open swimming space and routine maintenance.

Generally peaceful in a suitable community. Keep the recommended group of at least 6 fish and avoid mixing it with tank mates that need a very different temperature, water chemistry or swimming level.

Water and aquarium setup

A stable temperature of 21–26°C and pH of 6.0–7.5 are the working ranges in the planner. Stability and clean, oxygenated water matter more than chasing a single target number.

Use fine, smooth substrate and provide shaded caves or wood so bottom-dwelling fish can rest without damaged barbels.

Diet

Sinking omnivore pellets, frozen foods and occasional vegetables; feed after lights dim for nocturnal species.

Compatibility notes

Add only to mature tanks with biofilm and algae.

Use the Stocking & Bioload Planner to check a proposed community. Its estimated bioload value for one adult otocinclus is 0.57 units; this is a planning heuristic, not a replacement for testing nitrate.

Common mistakes

• Planning around the shop size instead of the adult size.
• Adding a schooling fish in a group smaller than its social minimum.
• Ignoring the tank's length, floor area or lid because the gallon number looks adequate.
• Adding fish before the aquarium is cycled and ammonia and nitrite are consistently zero.

Care ranges are conservative summaries of commonly cited husbandry references. Individual fish, strains and local water can differ; monitor the aquarium and adjust the plan gradually.