There is no way to contact the author, but I wanted to find them and let them know that that is not okay. It is not acceptable aquarist behavior to contaminate the local water bodies with anything from your aquarium, even a fish that came from the local water body. The reason is, once that fish has come into contact with the water from your tank, then they have also come into contact with any pathogen present.
Throughout the summer of 1992 I collected several green sunfish for my aquarium. Some had to be returned to their original body of water due to conflicts with the other sunfish already in the tank.
Many pathogens remain dormant for long periods of time, only expressing themselves when the fish has a lowered immune system. These "opportunistic" pathogens are riders, and will ride from one fish to another without you even knowing it was there. They would ride from the aquarium water to the native fish and back into the native ecosystem, infecting it and tainting it.
For this reason, it is not okay to release anything back into the water once it has contacted your tank. Even fish that originally came from that water may not be released back in. Find somewhere else to get rid of your pet. You can sell it on aquabid, you can give it away on craigslist, heck, I'd prefer to see a person kill that individual fish and toss it in the trash before I see them put it back in the local water body.
If anyone knows how to contact this Peter R. Rollo person so I can tell them that, I'd greatly appreciate it.
Edit: I wish I could change the title of this topic to add "once they've been introduced to a tank". Hmm. Whoops.
Edited by EricaWieser, 22 April 2011 - 09:57 AM.