hey danios are great hardy fish and they thrive in cold water need a school of 4 to 5. we keep ours in a 2foot cube with three gold fish and they are fine. other cold water varieties include paradise fish, specially bred platies can survive low temperature water, chinese algue eaters, bait fish, pacific blu eyes ect however these fish are much more sensitive than the danios. white clouds are also great we recently lost are last one to a hungry goldy
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
he way 7+ years old. best bet for cold water tanks are goldfish, danios and white clouds
hope that helps
kind regards liam m