Giant otocinclus (Hypoptopoma) (Hypoptopoma spp.) care guide

Group
Freshwater fish
Other names
Giant oto, Giant otocinclus, Hypoptopoma gulare, Hypoptopoma inexspectatum, Hypoptopoma thoracatum
Family
Loricariidae (suckermouth armoured catfishes)
Origin
South America east of the Andes: Amazon, Orinoco, Guiana and Paraná–Paraguay drainages (not the Atlantic coastal rivers between the Amazon mouth and the Paraná).
Water
freshwater
Maximum size
10.5 cm
Temperature
23–28°C
pH
6–7.5
Hardness
Soft to medium
Minimum tank
100 litres
Care level
intermediate
Temperament
peaceful

Care

Hypoptopoma are small to medium suckermouth catfish related to Otocinclus, often sold as "giant otos". Figures vary by species, so check the species before buying. PlanetCatfish lists 19 species with adult sizes of 3.6–10.5 cm SL (most about 7 cm). Wikipedia recognises 13 valid species. They have a stocky body, a wide, flattened head with the eyes set on the sides, and a concave head profile. H. gulare, the species most often kept by PlanetCatfish members, grows to 10.5 cm SL and comes from the Amazon basin, including the Marañón and Ucayali in Peru. Tank and group: they are sociable and do best in a group of four or more, in a tank of at least 100 litres (our estimate) with plenty of plants, wood and algae-covered surfaces. Gentle to moderate flow and good oxygen suit them. Water: PlanetCatfish gives no water figures. A tropical range of about 23–28 °C and soft to medium water at pH 6–7.5 is a sensible estimate based on their Amazonian origin; keep conditions stable and the water clean. Sexing and status: PlanetCatfish has no sexing notes. H. gulare is IUCN Least Concern (assessed 2020). Most fish are wild-caught imports. Sources: PlanetCatfish genus page (planetcatfish.com/hypoptopoma) and H. gulare (planetcatfish.com/common/species.php?speciesid=2534); Wikipedia (en.wikipedia.org/wiki/Hypoptopoma). Checked October 2026.

Diet

Grazers of algae and biofilm. Provide a mature tank with algae-covered surfaces, and supplement with algae wafers, spirulina-based foods and blanched vegetables such as courgette and spinach, with occasional small frozen foods. Newly imported fish are often thin, so check they are eating and keep food available.

Breeding

PlanetCatfish has no aquarium breeding report for H. gulare, and breeding in aquariums is rarely recorded for the genus. A well-fed group in a mature, heavily planted tank gives the best chance; any eggs found on plants or glass should be protected and the fry offered biofilm, crushed algae wafers and fine green foods.

Compatibility and tank mates

Very peaceful and timid. Keep them with small, calm community fish such as tetras, rasboras, pencilfish, Corydoras and dwarf cichlids. Avoid large, boisterous or territorial fish and bigger plecos that compete for algae and food.

Last updated 5 October 2026. Community-edited care guide on Aquatic-Auctions.

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