Goldfish color mutations have been in domestication for close to 2000 years now. The history of double tail and body mutations goes back about 700 years. Without them, the aquarium hobby as we know it today simply would not exist. Honestly I don't see what the ethical issue is with balloon fish is. They are natural mutations that we just happened to select for. Framed in that way, the fact that the mutation is appealing to some actually means that it facilitates the forward movement of the genetic line and ultimately the species itself. If one is to argue based on the health issues that come with the mutation, then long finned fish, many black livebearers, and basically albino everything goes out the window too. Not liking the aesthetics of balloon fish is one thing, but the vast majority of fishkeepers cannot ethically oppose naturally mutated balloon fish without suffering from some degree of hypocrisy. Phew. Rant over.