Only a few species of fish often sold from tropical aquariums are suitable for unheated aquariums. The term coldwater is slightly misleading as what we are normally referring to is unheated aquariums, temperate or sub tropical is a more accurate term. Provided a ‘coldwater’ aquarium is in a relatively warm room then they will probably have a temperature around 18C (65F). At this temperature they are several species that will be at home, these include Paradise Fish, Golden Barbs, Rosy Barbs, and Amano Shrimp. Mixing these fish with Goldfish is not recommended as many are too active to be mixed with Goldfish, especially fancy varieties. Due to the large size of Goldfish, they may eat many of the species listed above.