Fish Tanks

We have two fish tanks; a 55-gallon goldfish tank and a 29-gallon tropical fish tank. As our lives have gotten busier we stopped replacing fish when there were tank tragedies. We are still taking good care of the ones that are left, but are ready to be done with the responsibility. Last week we lost two fish-- one in each tank-- which was fully half of what was left. This means we now have a 55-gallon tank with one lone goldfish swimming around, as well as one Silver Dollar who has the 29-gallon tank all to himself. And since goldfish and tropical fish have different environmental needs, we can't combine the tanks. I feel badly for our little fishies, especially when I read about the goings-on in real fishkeepers tanks, and wish they could be in tanks filled with other fish buddies.