Can rummy nose tetras live with firemouth cichlids?

Verdict
Yes

Yes. Rummy nose tetras and firemouth cichlids make a good pair. Both are fine at 75–84°F. Plan on at least 30 gal.

Rummy nose tetraRummy nose tetra75–84°F · pH 5.5–7 Firemouth cichlidFiremouth cichlid75–86°F · pH 6.5–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 75–84°Rummy nose tetra 75–84°Firemouth cichlid 75–86°
The green band is the temperature range both can live in.
456789Both: 6.5–7Rummy nose tetra 5.5–7Firemouth cichlid 6.5–8
The green band is the pH both tolerate.

Size to scale

Rummy nose tetra · 2 inFiremouth cichlid · 6 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

Rummy nose tetraFiremouth cichlid
Temperature75–84 °F75–86 °F
pH5.5–76.5–8
Adult size2.0 in6.0 in
Minimum tank20 gal30 gal
TemperamentPeacefulSemi-aggressive
Swims atMiddleBottom
GroupGroups of 6+Alone or in pairs
DietOmnivoreOmnivore

Better tank mates for rummy nose tetras

All rummy nose tetra tank mates

Better tank mates for firemouth cichlids

All firemouth cichlid tank mates

Questions

Can rummy nose tetras live with firemouth cichlids?

Yes. Rummy nose tetras and firemouth cichlids make a good pair. Both are fine at 75–84°F. Plan on at least 30 gal.

What temperature suits both rummy nose tetras and firemouth cichlids?

75–84 °F. Rummy nose tetras need 75–84 °F, firemouth cichlids need 75–86 °F.

What size tank do rummy nose tetras and firemouth cichlids need together?

At least 30 gal, set by the firemouth cichlid. Add space for each extra fish.