Can black skirt tetras live with swordtails?

Verdict
Yes

Yes, black skirt tetras and swordtails can live together. Both are fine at 72–79°F. Plan on at least 30 gal.

Black skirt tetraBlack skirt tetra70–80°F · pH 6–7.5 SwordtailSwordtail72–79°F · pH 7–8.3

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–79°Black skirt tetra 70–80°Swordtail 72–79°
The green band is the temperature range both can live in.
456789Both: 7–7.5Black skirt tetra 6–7.5Swordtail 7–8.3
The green band is the pH both tolerate.

Size to scale

Black skirt tetra · 2.5 inSwordtail · 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

Black skirt tetraSwordtail
Temperature70–80 °F72–79 °F
pH6–7.57–8.3
Adult size2.5 in5.0 in
Minimum tank15 gal30 gal
TemperamentSemi-aggressiveSemi-aggressive
Swims atMiddleMiddle
GroupGroups of 6+Groups of 3+
DietOmnivoreOmnivore

Better tank mates for black skirt tetras

All black skirt tetra tank mates

Better tank mates for swordtails

All swordtail tank mates

Questions

Can black skirt tetras live with swordtails?

Yes, black skirt tetras and swordtails can live together. Both are fine at 72–79°F. Plan on at least 30 gal.

What temperature suits both black skirt tetras and swordtails?

72–79 °F. Black skirt tetras need 70–80 °F, swordtails need 72–79 °F.

What size tank do black skirt tetras and swordtails need together?

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