All fish / Loricariidae

Otocinclus flexilis

Otocinclus flexilis

Also known as oto, otocinclus, dwarf sucker catfish, flexible otocinclus, oto catfish, otto, オトシンクルス, 小精灵, 耳斑鲶

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A small sucker-mouthed catfish with a mottled brown back, pale belly and a dark stripe along the flank that is often broken up in this species. It comes from cooler subtropical waters further south than most otos and is kept for grazing soft algae and biofilm off plants and glass in planted tanks.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

4.5 cm

Temperature

18 to 25 °C

pH

6 to 7.5

Smallest tank

60 litres

Keep as

Group of 6 or more

Diet

Herbivore: biofilm, soft algae, blanched courgette and cucumber, algae wafers, with occasional small frozen foods

Swims

Bottom of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Southern Brazil, Uruguay and northeastern Argentina (Uruguay, Paraná and coastal drainages)

Breeding

Eggs are laid singly on plant leaves or glass after the group is conditioned with plenty of greens and cool water changes. It has been bred in home aquariums, though raising the tiny fry needs a steady supply of biofilm and fine foods.

Good to know

Wild-caught imports are often thin and stressed, so choose fish with rounded bellies and keep them in a mature tank with plenty of biofilm. Prefers cooler, well-oxygenated water than tropical otos and is easily confused with other Otocinclus species in the trade.