Can lemon tetras live with black neon tetras?

Verdict
Yes

Yes. Lemon tetras and black neon tetras get along in the same tank. Both are fine at 73–81°F. Plan on at least 15 gal.

Lemon tetraLemon tetra72–82°F · pH 5.5–7.5 Black neon tetraBlack neon tetra73–81°F · pH 5.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 73–81°Lemon tetra 72–82°Black neon tetra 73–81°
The green band is the temperature range both can live in.
456789Both: 5.5–7.5Lemon tetra 5.5–7.5Black neon tetra 5.5–7.5
The green band is the pH both tolerate.

Size to scale

Lemon tetra · 2 inBlack neon tetra · 1.5 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

Lemon tetraBlack neon tetra
Temperature72–82 °F73–81 °F
pH5.5–7.55.5–7.5
Adult size2.0 in1.5 in
Minimum tank15 gal15 gal
TemperamentPeacefulPeaceful
Swims atMiddleMiddle
GroupGroups of 6+Groups of 6+
DietOmnivoreOmnivore

Better tank mates for lemon tetras

All lemon tetra tank mates

Better tank mates for black neon tetras

All black neon tetra tank mates

Questions

Can lemon tetras live with black neon tetras?

Yes. Lemon tetras and black neon tetras get along in the same tank. Both are fine at 73–81°F. Plan on at least 15 gal.

What temperature suits both lemon tetras and black neon tetras?

73–81 °F. Lemon tetras need 72–82 °F, black neon tetras need 73–81 °F.

What size tank do lemon tetras and black neon tetras need together?

At least 15 gal, set by the lemon tetra. Add space for each extra fish.