Can ember tetras live with otocinclus?

Verdict
Yes

Yes. Ember tetras and otocinclus make a good pair. Both are fine at 73–79°F. Plan on at least 20 gal.

Ember tetraEmber tetra73–84°F · pH 5.5–7 OtocinclusOtocinclus72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 73–79°Ember tetra 73–84°Otocinclus 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7Ember tetra 5.5–7Otocinclus 6–7.5
The green band is the pH both tolerate.

Size to scale

Ember tetra · 0.8 inOtocinclus · 2 in0"1"2"3"4"5"6"
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

Ember tetraOtocinclus
Temperature73–84 °F72–79 °F
pH5.5–76–7.5
Adult size0.8 in2.0 in
Minimum tank5 gal20 gal
TemperamentPeacefulPeaceful
Swims atMiddleBottom
GroupGroups of 6+Groups of 6+
DietOmnivoreHerbivore

Better tank mates for ember tetras

All ember tetra tank mates

Better tank mates for otocinclus

All otocinclus tank mates

Questions

Can ember tetras live with otocinclus?

Yes. Ember tetras and otocinclus make a good pair. Both are fine at 73–79°F. Plan on at least 20 gal.

What temperature suits both ember tetras and otocinclus?

73–79 °F. Ember tetras need 73–84 °F, otocinclus need 72–79 °F.

What size tank do ember tetras and otocinclus need together?

At least 20 gal, set by the otocinclus. Add space for each extra fish.