fish with dropsy!

[daniella3d]

I have a bangai cardinal that has started to develop what looks like dropsy. Scales are raised away from the body and his belly is all swollen. He looks kind of puffy and does not eat anylonger. I am not sure what to do.

Would hyposalinity remove the excess fluid in his body?

I have hime for 2 months now and he's about 2 year old. Was tank raised. He was in quarantine for a month and was in perfect health, and no addition to the main tank recently as I always do 4 weeks quarantine.

What can this be? internal infection? kidney failure?