Can guppies live with otocinclus?

Verdict
Yes

Yes. Guppies and otocinclus get along in the same tank. Both are fine at 72–79°F. Plan on at least 20 gal.

GuppyGuppy72–82°F · pH 6.8–7.8 OtocinclusOtocinclus72–79°F · pH 6–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 72–79°Guppy 72–82°Otocinclus 72–79°
The green band is the temperature range both can live in.
456789Both: 6.8–7.5Guppy 6.8–7.8Otocinclus 6–7.5
The green band is the pH both tolerate.

Size to scale

Guppy · 2 inOtocinclus · 2 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

GuppyOtocinclus
Temperature72–82 °F72–79 °F
pH6.8–7.86–7.5
Adult size2.0 in2.0 in
Minimum tank10 gal20 gal
TemperamentPeacefulPeaceful
Swims atTopBottom
GroupGroups of 3+Groups of 6+
DietOmnivoreHerbivore

Better tank mates for guppies

All guppy tank mates

Better tank mates for otocinclus

All otocinclus tank mates

Questions

Can guppies live with otocinclus?

Yes. Guppies and otocinclus get along in the same tank. Both are fine at 72–79°F. Plan on at least 20 gal.

What temperature suits both guppies and otocinclus?

72–79 °F. Guppies need 72–82 °F, otocinclus need 72–79 °F.

What size tank do guppies and otocinclus need together?

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