George,
please see thread titled "Bluegill in a tank" under "Evaluating and adjusting fish populations". We had some discussions about fish tanks there in the spring. I am new to aquariums and presently only have 10 gal. one. The key to keeping fish alive seems to be the bacteria in the water, so you need to set it all up (WalMart has up to 75gal kits) about 2 wks prior to actually putting your desired fish in there. Put in some cheap, sacrificial fish, like guppies, or whatever you can seine. Once the algae starts growing on things, the water is properly conditioned for more sensitive fish. There is more to it than that, but you can find wealth of information by typing "Starting an aguarium" in your search engine.
If the Tilapia start overpopulating, I will put one or two of my bluegill in there for a while.
