This is an interesting debate, and one I've thought about. I myself, feel guilty for contributing to fish being caught, transported, with many dieing, only to go to people who don't care for them etc. I feel better knowing I'm getting a fish that is captive bred, as they've never experienced being "wild" etc. Others here would prefer wild caught, as they are a stronger species. I don't agree with taking that fish out of it's habitat, it should have been enjoyed there. If it is going to be caught, all efforts should be made to recreate it's natural environment, and knowledge about this fish and the commitment should be understood before hand.
But each of us have to know that our interest in fish, is what keeps fish from being bred, caught etc., and appreciate how many fish do have pretty doomed lives (in many cases) but not all, of course.
I don't eat meat, because I don't want to support and be a part of the horrible conditions these animals are raised in. That doesn't mean they are still not in bad conditions, but the more people move in that direction, the better for changing how we practice and care for animals in the industry of food.
My 2 cents. The fish can't go back now, unless this person does live close enough to get it back. The effort now is giving it the best habitat. A stark tank, by himself doesn't seem in the fish's best interest. IMO
Just because animals can't talk, does not mean they should not be heard