I am sure that during this time there was a proliferation of algae and microorganisms of some sort, and the damsel basically went for its natural diet.
Though with other dead fish and animals it likely ate that too.
When you think about it this is not a great deal different than a high tidepool with the advantage of not being overly hot. It was a long slow acclimation to a higher specific gravity...I am not really surprised it is alive, personally, simply based on the salinity question.
I have to wonder, why did you not have someone come in to at least put water in, if nothing else? I think this this was a rather questionable thing to do to animals, personally.
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I assume you expected all of them to die because you are suprised one is alive? If so, I think in the future it would be more humane to kill animals quickly than in this way.
Personally, I don't recommend setting up the tank again unless you are really settled and expect no more long trips.
sorry to sound harsh but I'm scratching my head a bit on this one.
or I would be if I had the smiley for it.