When we were kids we used to catch fish out of the lake and put them in my neighbor's pool. Obviously the pool was in disrepair and all chlorine had dissipated. We put bass, bream, catfish, shellcrackers, warmouths, gar, thousands of ghost shrimp, mollies, you name it. Our neighbor didn't know we were doing anything of the sort for weeks until he saw a small school of shiners swim past him one morning. It was killer.