Can rainbow sharks live with black skirt tetras?

Verdict
Yes

Yes. Rainbow sharks and black skirt tetras get along in the same tank. Both are fine at 72–80°F. Plan on at least 55 gal.

Rainbow sharkRainbow shark72–80°F · pH 6.5–7.5 Black skirt tetraBlack skirt tetra70–80°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–80°Rainbow shark 72–80°Black skirt tetra 70–80°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Rainbow shark 6.5–7.5Black skirt tetra 6–7.5
The green band is the pH both tolerate.

Size to scale

Rainbow shark · 6 inBlack skirt tetra · 2.5 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

Rainbow sharkBlack skirt tetra
Temperature72–80 °F70–80 °F
pH6.5–7.56–7.5
Adult size6.0 in2.5 in
Minimum tank55 gal15 gal
TemperamentSemi-aggressiveSemi-aggressive
Swims atBottomMiddle
GroupOne per tankGroups of 6+
DietOmnivoreOmnivore

Better tank mates for rainbow sharks

All rainbow shark tank mates

Better tank mates for black skirt tetras

All black skirt tetra tank mates

Questions

Can rainbow sharks live with black skirt tetras?

Yes. Rainbow sharks and black skirt tetras get along in the same tank. Both are fine at 72–80°F. Plan on at least 55 gal.

What temperature suits both rainbow sharks and black skirt tetras?

72–80 °F. Rainbow sharks need 72–80 °F, black skirt tetras need 70–80 °F.

What size tank do rainbow sharks and black skirt tetras need together?

At least 55 gal, set by the rainbow shark. Add space for each extra fish.