Can guppies live with hillstream loaches?

Verdict
Yes

Yes. Guppies and hillstream loaches make a good pair. Both are fine at 72–75°F. Plan on at least 20 gal.

GuppyGuppy72–82°F · pH 6.8–7.8 Hillstream loachHillstream loach68–75°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–75°Guppy 72–82°Hillstream loach 68–75°
The green band is the temperature range both can live in.
456789Both: 6.8–7.5Guppy 6.8–7.8Hillstream loach 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Guppy · 2 inHillstream loach · 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

GuppyHillstream loach
Temperature72–82 °F68–75 °F
pH6.8–7.86.5–7.5
Adult size2.0 in2.5 in
Minimum tank10 gal20 gal
TemperamentPeacefulPeaceful
Swims atTopBottom
GroupGroups of 3+Groups of 3+
DietOmnivoreHerbivore

Better tank mates for guppies

All guppy tank mates

Better tank mates for hillstream loaches

All hillstream loach tank mates

Questions

Can guppies live with hillstream loaches?

Yes. Guppies and hillstream loaches make a good pair. Both are fine at 72–75°F. Plan on at least 20 gal.

What temperature suits both guppies and hillstream loaches?

72–75 °F. Guppies need 72–82 °F, hillstream loaches need 68–75 °F.

What size tank do guppies and hillstream loaches need together?

At least 20 gal, set by the hillstream loach. Add space for each extra fish.