
A little late here, but just wanted to add a note about Epsom salts. Popeye is a bacterial infection caused by poor water conditions. As CobettaCouple stated medication is indicated, and suggested what I would use.
The use of Epsom salts has been referred to in the treatment of Dropsy. This is basically kidney failure in fish, and results in the retention of water. The use of a small amount of Epsom salts in a quarantine situation with the one fish can be useful, it helps draw the water out of the fish, but the underlying problem of kidney failure has to also be addressed with antibiotics, and is very rarely successful.
Good Luck with the popeye! The water changes are very useful, if I were you I would do tests to determine just what the ammonia, nitrite and nitrate are, to make sure your tank stays healthy in the future. Nitrates over 20 can cause the problems you are currently having, and others like fin rot etc..