I would finish the current Maracyn 2 treatment cycle, and also add the following two things:
a) Maracyn (Erythromycin)
b) Epsom salt.
Epsom salt (magnesium sulfate) can help relieve the fluid retention/swelling in the eye. You can get this at supermarkets and pharmacies (but not pet stores). Look for 100% magnesium sulfate. (No dyes, additives or perfumes.)
You didn't say the size of your tank, so I can't give you specific amounts, but here's the general procedure:
- Put some of his tank water in a cup. Stir in Epsom salt so that you'll have a dosage of 0.5 teaspoons Epsom salt/gal. Make sure the salt is completely dissolved.
-- 1 gal tank: Dissolve 0.5 teaspoons Epsom salt.
-- 2 gal tank: Dissolve 1 teaspoon Epsom salt.
- Slowly, over the course of about 30 minutes, pour the dissolved Epsom salt mixture into the tank.
- Wait 12 hours. Then repeat the above process. This will take you to a total dosage of 1 teaspoon Epsom salt per gallon.
- When doing water changes during his treatment, use new water that contains conditioner and Epsom salt (1 teaspoon/gal). This will maintain his 1 tsp/gal dosage for the duration of his treatment.
I would also try to increase the humidity level in the tank. This will make it easier for him to breathe, and has a calming effect. One way to do this is to put plastic food wrap (Saran, Glad, etc) over the top of the tank. Make sure you leave several inches of air, so he can breathe.
As for not eating, what are you feeding him? If you tell us that, people may be able to give you suggestions on how to entice him to eat.