Otocinclus Catfish
Otocinclus sp. · Peaceful · Intermediate care
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The hobby's favourite little algae cleaner — a 4 cm suckermouth catfish that spends all day rasping soft algae from glass, plants and wood. Peaceful, tireless and completely plant-safe.
At a glance
Species profile Otocinclus sp.
Origin
Rivers and streams across South America
Family
Loricariidae (suckermouth catfish family)
Adult size
Up to 4 cm (1.6 in)
Diet
Soft green/brown algae and biofilm, plus blanched vegetables and algae wafers (Herbivore)
Temperament
Peaceful
Swimming level
All levels (grazes surfaces)
Minimum group
6+ (shoaling)
Lifespan
3-5 years
Minimum tank
60 L (15 gal)
Water type
Freshwater
Size to scale
4 cm adult length, shown to scale against an iPhone 15 Pro (14.66 cm).
Natural range
Where it comes from — South America
Rivers and streams across South America
Water
Singapore tap water vs its needs
Hardness: Soft to medium (2-15 dGH).
In the aquarium
How it lives in the tank
Swims at every level of the tank
Keep in a group of 6+
Sensitivity Index — Moderate
Adaptable, but happiest with stable parameters in a matured tank.
Our own read on how forgiving this species is of water changes — not a formal standard.
Keeping & care
What this fish needs
Family
About the Loricariidae family suckermouth catfish family
Loricariidae are the armoured suckermouth catfishes — the plecos — a huge South American family clad in bony plates with a ventral sucker-mouth for grazing surfaces and holding station in current. They range from the tank-friendly bristlenose (Ancistrus) and dwarf 'L-number' plecos up to the massive common pleco that outgrows most tanks. Most are peaceful and nocturnal and appreciate driftwood to rasp on, though diets vary from algae to wood to protein by species.
Give plecos driftwood and caves, feed to their actual diet (algae wafers, vegetables, or protein/wood by species), and always check adult size — many sold small grow far too large for community tanks.
Breeding
Cave-spawner (male-guarded)Many smaller plecos, especially bristlenose, are cave-spawners that breed readily: the female lays a clutch inside a snug cave or pleco log and the male guards and fans it until the yolk-sac fry emerge. Provide correctly-sized caves, good feeding and a cooler water change to trigger spawning; larger and fancy L-number plecos are progressively harder and some are rarely bred.
Feeding
Recommended food
Compatibility
Best tankmates
Community
