Variations
1 kinds · tap one for a closer look
Otocinclus
A tiny algae-eating catfish. Needs a mature tank with plenty of soft algae.
Fish sold as otocinclus are often Otocinclus macrospilus or O. vestitus, not O. vittatus. Care is the same.
- Tinfoil barb eats animals up to about 5 cm. Otocinclus only grows to 3.3 cm.
- Giant gourami eats animals up to about 10 cm. Otocinclus only grows to 3.3 cm.
- Angelfish eats animals up to about 4 cm. Otocinclus only grows to 3.3 cm.
- Only a narrow temperature range suits both: 24–25 °C.
- Only a narrow temperature range suits both: 24–25 °C.
- Only a narrow temperature range suits both: 24–25 °C.
281 species in our list are a good match.
Care and water
Behavior
Peaceful group fish; perfect with shrimp.
Food
Algae, wafers, blanched vegetables.
Tap a food to see what it is.
Male or female
Health
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Breeding
Rarely bred in captivity ·
Rarely bred in tanks; after a Corydoras-style T-position, females lay eggs on plants and the tank glass.
Group of 6+ in a mature tank. Males are smaller.
A mature planted tank with algae biofilm.
Water changes with cooler water.
Small egg groups on glass or plants; hatch in about 2-3 days.
Fry feed on biofilm and fine algae.
- Starving them in a clean tank
- Hard water
- Not feeding algae foods
Where it lives in the wild
The story of the otocinclus
A tiny sucker-mouth catfish that grazes soft algae. Delicate when first imported; best in mature tanks.
C. Tate Regan described this small armoured catfish in 1904. Otocinclus live in groups on vegetation, grazing algae and biofilm from leaves. Aquarists value them as gentle algae eaters, though most are still wild-caught.
First described by C. Tate Regan in 1904.
- It grazes on biofilm and soft algae.
- It is best kept in groups.
- It can gulp air at the surface.
Sources
14 facts checked with sources
- Scientific name
The name is valid (Regan, 1904), BUT fish sold as 'otocinclus' are a mix of several look-alike species. Seriously Fish says O. macrospilus is frequently sold labelled as O. vittatus or O. affinis, and O. vestitus is also sold as the 'dwarf otocinclus'. O. vittatus itself is one of the commonly imported species (ScotCat: 'One of the most common of the Otocinclus species that is imported'). Recommend the site present this as 'Otocinclus spp. (commonly O. vittatus, O. macrospilus, O. vestitus)' or keep vittatus with a note.
Eschmeyer's Catalog of Fishes: Otocinclus vittatus · Seriously Fish: Otocinclus macrospilus (Oto) · Wikipedia: Otocinclus vestitus (citing IUCN, Catalog of Fishes, PlanetCatfish) - Family
Subfamily Hypoptopomatinae (Catalog of Fishes agrees).
FishBase: Otocinclus vittatus - Sizecorrected
FishBase 3.3 cm TL preferred for size; ScotCat (hobby site) gives 4.0 cm. The often-mislabelled O. macrospilus reaches 35 mm SL (Seriously Fish), so 3.5-4 cm is realistic for trade 'otos' in general.
FishBase: Otocinclus vittatus · ScotCat: Otocinclus vittatus (hobby reference) - Temperaturecorrected
No Seriously Fish page for O. vittatus. Sources disagree: FishBase 20-25 °C, ScotCat 25-28 °C; Seriously Fish gives 21-26 °C for the look-alike O. macrospilus. FishBase used as value; a reviewer might keep a compromise such as 21-26.
FishBase: Otocinclus vittatus · ScotCat: Otocinclus vittatus · Seriously Fish: Otocinclus macrospilus - pHFishBase: Otocinclus vittatus · ScotCat: Otocinclus vittatus
- Hardness
Site range is inside FishBase's 2-18 dH. (Seriously Fish gives 1-12 dGH for O. macrospilus.)
FishBase: Otocinclus vittatus - Smallest tank
No tank size found for O. vittatus itself. For the look-alike O. macrospilus (often sold as vittatus), Seriously Fish gives a 45 x 30 cm base: 45 x 30 x 30 cm = 40.5 L (~41 L). The site's 60 L is more generous than that, so it is not unsafe; reviewer can decide whether to apply the macrospilus figure.
Seriously Fish: Otocinclus macrospilus - Group size
No group size found for O. vittatus itself; for the look-alike O. macrospilus Seriously Fish says at least 6 (legacy also said 6). If the site applies that, change 5 -> 6.
Seriously Fish: Otocinclus macrospilus - Temperament
No source for O. vittatus. For O. macrospilus, Seriously Fish calls it 'very shy and retiring' and recommends small, peaceful tankmates, which supports 'peaceful' in substance for trade otos, but not for vittatus specifically.
Seriously Fish: Otocinclus macrospilus - Swimming level
FishBase 'demersal' = living on or near the bottom. In tanks otos also graze plants and glass at all heights (legacy said 'all'), so 'bottom' is defensible but not the whole picture.
FishBase: Otocinclus vittatus - Care level
No rating for O. vittatus. Seriously Fish rates the look-alike O. macrospilus 'Moderate' and stresses mature, planted tanks with plenty of algae and microorganisms, consistent with the site's 'moderate' and its summary text.
Seriously Fish: Otocinclus macrospilus - Where it livescorrected
Site has no value; sourced value supplied. Country list from the Catalog of Fishes entry.
FishBase: Otocinclus vittatus · Eschmeyer's Catalog of Fishes: Otocinclus vittatus - Male or female
No sexing source for O. vittatus. For O. macrospilus, Seriously Fish says mature females 'appear broader in the body' seen from above, which agrees in substance with the legacy text (females larger, rounder).
Seriously Fish: Otocinclus macrospilus - Breedingcorrected
Egg placement confirmed by ScotCat (hobby reference; it still lists O. macrospilus as a synonym, so its account may mix species). The legacy 2-3 day hatch time was not found in any source and is dropped. Seriously Fish (O. macrospilus) instead says eggs are 'scattered randomly around the tank'. Wikipedia: trade fish are 'almost always wild caught'.
ScotCat: Otocinclus vittatus (hobby reference)