Hmmmm...
lets run through some things...
i understand when you got him he was kept in F/W and i know you planned on getting salinity levels up...
question is:
1. How fast did you raise the salinity level and by how much each time from fresh and did you use a refractometer or similar tool to measure when doing it?
2. was there any tank mates in the tank?
3. How long was he kept in fresh water if you know?
4. what temps are the tank kept at?