sick borelli

[anewbie]

What would cause this to happen to a fish (it is still alive though i suspect not for long). I've had him for a bit over 18 months and i suspect he was around 6 months old when purchased though that is a bit difficult to tell. He is a domestic opal strain borelli:


He was fine yesterday. Not over joyed with this as it doesn't seem to be 'old fish' sympton.

 

[anewbie]

I guess what i'm asking is what would make a fish fold up like that and if there is much i can do at this point. This morning his gills were still functioning but beyond that he cannot move.