I totally agree about not releasing aquarium fish into the wild. I didn't even know that the native fish could get diseases from the aquarium fish, but the reason I disagree with releasing pet fish is because it's just not moral. It would be like releasing a pet bird outdoors because you didn't want it anymore -- it's just plain wrong. I do not believe in the 'disposable' pet theory with any kind of pet. When you make the commitment to take care of another living creature it is a lifelong commitment. If you cannot follow through, it is your duty to find that creature an appropriate new loving home.