From the category archives:

Cold Water Fish

Family: Cyprinidae
Distribution: Carassius auratus auratus, best known as the Goldfish, has its origins in central Asia and China, and Japan.  The species, which inhabits ponds, rivers, lakes and ditches – particularly in slow-flowing waters – has since been introduced throughout the world.
PH: 6.0 – 8.0
Temperature: 15°C – 30°C (59 – 86F)
Hardness: 5 – 19 dH
[...]