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No federal permit to keepOtocinclus macrospilus
Otocinclus macrospilus
Fishes › Catfish (Siluriformes) › Loricariidae (Plecos)
Otocinclus macrospilus, the tailspotted oto, dwarf otocinclus or dwarf sucker, is a species of freshwater ray-finned fish in the armored catfish family Loricariidae.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 1.4 in / 3.5 cm).
- Water: Freshwater.
- Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
- Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 18 × 12 in (roughly 11 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 70–79 °F, pH 5.5–7.5, 1–12 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Ideally keep it in a heavily planted setup with broad-leaved plants, driftwood branches and, if you wish vertical rock surfaces.”
- Diet: “It feeds primarily on algae and other microrganisms in nature.”
- Tankmates: “Very shy and retiring, to the point that it will be out-competed for food by more vigorous species.”
- Breeding: “Has been achieved, but unfortunately very few details are available.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Plecos (suckermouth catfish)
Applies to most species in this group. Habitat: South American rivers. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Driftwood (some species rasp it for fiber), caves and good flow.
- Common plecos reach 18–24 in; many smaller species stay under 6 in.
Diet
- Algae wafers and vegetables for herbivores; meaty foods for carnivorous species.
Health watch
- Starvation if they're expected to live on algae alone.
Understanding the animal
About this animal
About this animal
It is native to South America, where it is found in the upper Amazon basin in Colombia, Ecuador and Peru.
Quoted from the Wikipedia article “Otocinclus macrospilus” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. Stays near the bottom. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 88°F (up to 89°F in the hottest sampled areas) |
| Cool-season lows | about 68°F (down to 66°F in the coldest sampled areas) |
| Average temperature | 77–80°F across sampled records |
| Relative humidity | 83–85% on average (driest month about 81%) |
| Rainfall | about 2776 mm a year, spread fairly evenly |
Measured at 34 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | Otocinclus macrospilus, the tailspotted oto, dwarf otocinclus or dwarf sucker, is a species of freshwater ray-finned fish in the armored catfish family Loricariidae. It is native to South America, where it is found in the upper Amazon basin in Colombia, Ecuador and Peru. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| History and naming | The tailspotted oto is one of the commoner species of Otocinclus found in the aquarium trade, where it is frequently mislabeled as O. affinis or O. vittatus. It has been bred in captivity, but most specimens remain wild-caught. — Wikipedia (community-edited) |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 18 × 12 in (about 11 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
- Seriously Fish — Ancistrus sp. “3” / common bristlenose identification Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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