I second the pacu idea, they grow very fast and really are not suited for aquaria life. By growing it as large as you can and than eating it you would actually be doing it a favor.
alot of the chemicals that we use in our tanks say clearly that they are for fish that aren't to be consumed. What is the deal with that? i dont eat fish anyways, but it seems to me that it cant be healthy.
Well if you intend on eating the fish, don't use the chemicals. Seems simple. Besides that, I would trust a home grown ifsh over a wild caught or farmed one.