If the HITH is that pronounced, the humane thing to do would be to put it out of its misery (IMO IMO IMO!). Seriously, if you can see down to the bone of the fish, I'd venture a guess that it has multiple other problems that you don't see. I'm sure there are some people who would argue that you could turn it around with vigorous water changes, impeccable tank maintenance, and good food, but the chances are slim that someone will walk into that store and see the fish in that condition, then actually pay money for it and dedicate the time and tank space required to turn it around. Sad but true. I see sickly adult oscars here all the time that people trade in, and they're all over Craigslist as well (along with the 55 gallon tank that they were improperly raised in).
