Can otocinclus live with arowanas?

Verdict
No

No. Otocinclus and arowanas should not share a tank. An adult silver arowana 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: 75–79°Otocinclus 72–79°Silver arowana 75–86°
The green band is the temperature range both can live in.
456789Both: 6–7Otocinclus 6–7.5Silver arowana 6–7
The green band is the pH both tolerate.

Size to scale

Otocinclus · 2 inSilver arowana · 36 in0"6"12"18"24"30"36"
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

OtocinclusSilver arowana
Temperature72–79 °F75–86 °F
pH6–7.56–7
Adult size2.0 in36.0 in
Minimum tank20 gal250 gal
TemperamentPeacefulAggressive
Swims atBottomTop
GroupGroups of 6+One per tank
DietHerbivoreCarnivore

Better tank mates for otocinclus

All otocinclus tank mates

Questions

Can otocinclus live with arowanas?

No. Otocinclus and arowanas should not share a tank. An adult silver arowana eats fish that fit in its mouth, and at 2 inches otocinclus do.

What temperature suits both otocinclus and arowanas?

75–79 °F. Otocinclus need 72–79 °F, arowanas need 75–86 °F.

What size tank do otocinclus and arowanas need together?

At least 250 gal, set by the silver arowana. Add space for each extra fish.