I have a star fish that I have kept for 2 years. 3 months ago, I had an accident where the salinity drifted down to below 1.016. The body of this star fish blew up like a balloon. After I fixed the problem, the body returned to normal size, but large chunks of the body rotted and came off in between the legs. Several weeks later, it seems to be more active, but sections of its legs are falling off. Once whole leg came off entirely and the other legs keep loosing segments. But the poor thing is still alive after 3 months and still crawl around the tank. I don't know how it is surviving since it will not eat. Attach are photos of the remaining body and a sample segment of a broken off leg. Some of these broke off segments will stay alive and move on its own for days. Is there anything I can do to help this thing recover?

welcome to RAF nanowiz!

Ooh, that's not good. Unfortunately the best thing you can do is maintain impeccable water quality. Seastars aren't designed very well for salinity fluctuations, so they get irreversible cell damage when that happens due to the change is osmotic pressure. Like you saw, the tissue fills with water and many of the cells will literally rupture from the inflation. The only way the seastar will recover is if it has at least one arm with a little of the stomach attached, if it's just the arm, it will die because it has no way of eating.

I've never had a star survive that kind of damage for as long as yours has, so it might recover if you keep the water as stable as possible, especially since it's held on so long. However, there's a real good chance it could die too.