Can oscars live with otocinclus?

Verdict
No

No. Oscars and otocinclus should not share a tank. An adult oscar eats fish that fit in its mouth, and at 2 inches otocinclus do.

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 74–79°Oscar 74–81°Otocinclus 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7.5Oscar 6–8Otocinclus 6–7.5
The green band is the pH both tolerate.

Size to scale

Oscar · 12 inOtocinclus · 2 in0"2"4"6"8"10"12"
Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

OscarOtocinclus
Temperature74–81 °F72–79 °F
pH6–86–7.5
Adult size12.0 in2.0 in
Minimum tank75 gal20 gal
TemperamentSemi-aggressivePeaceful
Swims atMiddleBottom
GroupAlone or in pairsGroups of 6+
DietCarnivoreHerbivore

Better tank mates for oscars

All oscar tank mates

Better tank mates for otocinclus

All otocinclus tank mates

Questions

Can oscars live with otocinclus?

No. Oscars and otocinclus should not share a tank. An adult oscar eats fish that fit in its mouth, and at 2 inches otocinclus do.

What temperature suits both oscars and otocinclus?

74–79 °F. Oscars need 74–81 °F, otocinclus need 72–79 °F.

What size tank do oscars and otocinclus need together?

At least 75 gal, set by the oscar. Add space for each extra fish.