Otocinclus tank mates
The true peaceful algae-eater. Extremely sensitive to new tanks and ammonia spikes. A high-mortality fish when added too early.
Lists below are built from this species record (safest, best with, risky, unsafe) — each link opens a pair-level check, not a guarantee.
Best tank mates (on file)
Merged from conservative safest and best with fields — de-duplicated by species.
The Otocinclus profile lists Betta as both safe and a recommended pairing. Betta is a semi-aggressive beginner-care species with a 20L minimum. Run the pair checker for your specific tank before stocking.
The Otocinclus profile lists Cherry Barb as both safe and a recommended pairing. Cherry Barb schools in groups of 6 or more, so plan room for the whole group rather than one fish.
The Otocinclus profile lists Corydoras Catfish as both safe and a recommended pairing. Corydoras Catfish schools in groups of 6 or more, so plan room for the whole group rather than one fish.
The Otocinclus profile lists Guppy as both safe and a recommended pairing. Guppy is a peaceful beginner-care species with a 40L minimum. Run the pair checker for your specific tank before stocking.
The Otocinclus profile lists Neon Tetra as both safe and a recommended pairing. Neon Tetra schools in groups of 6 or more, so plan room for the whole group rather than one fish.
Risky or situational
From risky tank mates and broad avoid with (excluding “unsafe” below). May work with species-only setups, more water, or mature systems — read the pair page.
None on file beyond the safe list.
Fish to avoid with Otocinclus
From the unsafe list — predation, aggression, or space rules on this profile.
Oscar reaches 35cm and is flagged predatory. Otocinclus at 5cm is prey-sized for it. Oscar needs at least 300L, far above the 60L minimum for Otocinclus. The tank that houses one stresses the other. Oscar is rated aggressive and Otocinclus is rated peaceful. No community-style planning carries that gap.
Tiger Barb conflicts with Otocinclus on temperament, predation, or footprint. The juvenile size in a shop tank is not the figure that matters here.
Jack Dempsey reaches 25cm and is flagged predatory. Otocinclus at 5cm is prey-sized for it. Jack Dempsey needs at least 200L, far above the 60L minimum for Otocinclus. The tank that houses one stresses the other. Jack Dempsey is rated aggressive and Otocinclus is rated peaceful. No community-style planning carries that gap.
Tank size and groups
- Published minimum for Otocinclus: 60L — group minimum 4 (schooling).
- Compatibility changes when the tank is too short for turning, too little for a real school, or too warm for one species and not the other — that is why pair checks include tank context, not only temperament.
- Nearest litre hub to this minimum: 60L hub.
Easier alternatives to consider
Conservative beginner-peaceful picks from the library — not replacements for reading, but a shorter on-ramp than this species for a first tank.
Plan before you buy
Pair checks for every mix, then multi-species stocking in the builder.
Filtration & heating
A 60L minimum tank for Otocinclus needs a filter rated for at least 240L/hr turnover and a heater maintaining 20–27°C.
Similar fish (same category)
- Bristlenose Pleco — min 80L
- Siamese Algae Eater — min 100L
- Clown Pleco — min 110L
- Royal pleco — min 500L
- Common Pleco — min 600L
Related (care + temperament)
Other species that list Otocinclus
Reverse lookup: these profiles reference Otocinclus under safe or “best with” lists.