They are a true coolwater species, meaning they are actually stressed and do not do well over a certain temp. This is different from goldfish who are not stressed at higher temps. White clouds should be in a room temp tank (or barely above room temp just to keep the temp stable). Other fish in the tank need to have the same needs. Livebearers are an option (platies, guppies, mollies, and swordtails), as well as other danios like all zebra danio varieties (wild/zebra, gold, blue, leopard, and all the longfinned varieties). There are others as well. When looking up actual, accurate data for temps use fishbase.org. This will give you accurate information about their actual needs.