Can fancy goldfish live with dojo loaches?

Verdict
Yes

Yes. Fancy goldfish and dojo loaches make a good pair. Both are fine at 65–74°F. Plan on at least 55 gal.

Fancy goldfishFancy goldfish65–74°F · pH 7–8 Dojo loachDojo loach59–77°F · pH 6.5–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 65–74°Fancy goldfish 65–74°Dojo loach 59–77°
The green band is the temperature range both can live in.
456789Both: 7–8Fancy goldfish 7–8Dojo loach 6.5–8
The green band is the pH both tolerate.

Size to scale

Fancy goldfish · 6 inDojo loach · 6 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

Fancy goldfishDojo loach
Temperature65–74 °F59–77 °F
pH7–86.5–8
Adult size6.0 in6.0 in
Minimum tank30 gal55 gal
TemperamentPeacefulPeaceful
Swims atAll levelsBottom
GroupAlone or in pairsGroups of 3+
DietOmnivoreOmnivore

Better tank mates for fancy goldfish

All fancy goldfish tank mates

Better tank mates for dojo loaches

All dojo loach tank mates

Questions

Can fancy goldfish live with dojo loaches?

Yes. Fancy goldfish and dojo loaches make a good pair. Both are fine at 65–74°F. Plan on at least 55 gal.

What temperature suits both fancy goldfish and dojo loaches?

65–74 °F. Fancy goldfish need 65–74 °F, dojo loaches need 59–77 °F.

What size tank do fancy goldfish and dojo loaches need together?

At least 55 gal, set by the dojo loach. Add space for each extra fish.