What fish can you put with goldfish?

Goldfish are best with goldfish with the exception of weather (dojo) loaches, or bristlenose plecos.
Goldfish need 20 gallons for the first fish, and 10 gallons each per additional goldfish (30 gallons for 2 goldfish). If you have a 40 gallon tank for example, you could have 2 goldfish, and 1 bristlenose pleco without being overstocked.