Can congo tetras live with serpae tetras?

Verdict
Yes

Yes. Congo tetras and serpae tetras make a good pair. Both are fine at 73–79°F. Plan on at least 30 gal.

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 73–79°Congo tetra 73–82°Serpae tetra 72–79°
The green band is the temperature range both can live in.
456789Both: 6–7.5Congo tetra 6–7.5Serpae tetra 6–7.5
The green band is the pH both tolerate.

Size to scale

Congo tetra · 3 inSerpae tetra · 1.75 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

Congo tetraSerpae tetra
Temperature73–82 °F72–79 °F
pH6–7.56–7.5
Adult size3.0 in1.75 in
Minimum tank30 gal20 gal
TemperamentPeacefulSemi-aggressive
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for congo tetras

All congo tetra tank mates

Better tank mates for serpae tetras

All serpae tetra tank mates

Questions

Can congo tetras live with serpae tetras?

Yes. Congo tetras and serpae tetras make a good pair. Both are fine at 73–79°F. Plan on at least 30 gal.

What temperature suits both congo tetras and serpae tetras?

73–79 °F. Congo tetras need 73–82 °F, serpae tetras need 72–79 °F.

What size tank do congo tetras and serpae tetras need together?

At least 30 gal, set by the congo tetra. Add space for each extra fish.