Hi I read on here that platys are a tropical fish and should be kept in a heated tank. yet originally I was sold two platys as coldwater fish to go in with two then newly acquired goldfish tank. I have the two platys at mo in with some cloud minnows and few danios in an unheated tank. I also have 4 fancies in another separate tank. I am upgrading my goldie tank to a 300l soon I would like to have all my fish in the one tank. Can I put the minnows in with the danios in the goldie tank. And then get a smaller tank and heater for my platys. I don't have room for three tanks. Or can I keep the plays, minnow and danios together and just get a heater for there current tank and then have the goldie on there own in a 79gallon. My platys have lived fine for almost a year in a coldwater tank its just I feel bad if they aren't meant to be in there. Any advice will be good. What is the best suggestion. I also worry that if I put minnow in with the goldies as they get older they will mistake them as food!!! I want no more than two tank ie spacewise and workwise. I wouldn't have got the platys if I knew they were not meant for coldwater.