What is this on my bloated fish ?

[dudley]

Also on the epsom salt; how long should the fish be left in the the water with epsom salt? Is it a dip where a few minutes or should he be left in it for several days?

At least several days and longer if you start to see improvements as long as the fish tolerates it.

 

[fishorama]

I agree with dudley, it doesn't usually bother fish. Just remove it gradually after a week or so with water changes. Good luck!