Okay here is my take, for what it is worth. It is a fish. You bought it not knowing that in the future you would want something that it may be detrimental to. Put it in the sump. If it lives more power to it and you. IMO chances are it will be alright, people purchase them and put them in tanks with no SPS and they live. It seems you do more than most to take care of the creatures you have in the sump and have actually added some creatures because you wanted them but not in the display so how is this different. You, IMO, are putting too much emotion into the decision of what to do. I'll, at the risk of losing your friendship, question the amount of money, time and emotional distress you put into trying to save Bigun. Don't get caught up in the same thing here. We do our best and sometimes we come up short. You don't know what is gonna happen with putting it in the sump, but you do know what will happen if you put it in a baggie in the freezer, you flush it down the Oklahoma sewer system etc.
Put it in the sump, try to maintain it to the best of your ability and realize that it is a fish and you have done what you can under the circumstances you have.
You are a big city New York girl, get ahold of yourself here.
...but I also didn't really want it in my 29g either.....the 1st went in kinda by a spur of the minute boo boo...
