I have just bought a new RES from a pet store that was not taking very good care of him. He is now in a tank with one other RES.They only problem is he is a little big for my tank and I need to know what size tank I should get for them. The new guy is about 4 inches and the little guy is about 2. I also need to know what type of filter to get the one I have now is pretty old and does not do a good job of cleanig the tank. I have a 15 gallon tank and I know it is too small! Please help me!!

