Please rehome that paradise fish. I have a trio myself and they are very active fast swimming little things that really deserve an absolute minimum of 2ft of swimming space. They have an intelligence and insatiable curiosity similar to the larger preds (and a ferocity to match) so he is likely bored out of his mind too. To those saying get a heater, its probably not worth it unless the tank is close to freezing. These fish are very hardy and do very well at room temp or even in ponds if you live somewhere it wont freeze over. I know how easy it is to make these sort of mistakes but a little research would show you how colourful a healthy paradise fish is. Here are my ladies and they are no where near as colourful or as large as a male:
I started out with them in a 29g but they needed more space and are now happily enjoying a 75g with the male and some fast swimming shoalers but as you can see they still spar over territory.
Last edited by ony; 12-02-2012 at 08:27 PM.