Puffer problem

[fono15200]

I have a 55 gallon tank with one spotted puffer in it. There are other fish in the tank, but he gets along very well with them. Ive had the puffer for right at a year, and have never had a problem with him.

Heres the problem

Starting a few weeks ago, the puffers face almost looks like the skin is peeling off between the eyes. Hes not anywhere near as active as he used to be and his belly stays brown more than white. He used to love snails, but has stopped eating the small ones, but still eats the freeze dried shrimp and blood worms. Love this little fish, dont want anything to happen to him..have used two medicines: Api Stress Coat and am on day two of using Api Melafix. So far not any change.

[stevenallenbarnard]

what's your filtration like? this could be a big issue

[Mzungu]

What is a spotted puffer? A "GSP?" Or some other kind? Is this tank brackish, FW, SW?

[fono15200]

Brackish, have two Emperor Bio-Wheel filters and undergravel filter with two power heads

[Mzungu]

We're going to need to know a lot more to be able to help.

History of the tank, if any new fish were added recently, what the specific gravity or salinity is, water change schedule, what you're feeding the fish (Anything besides shrimp and bloodworms? Are those both freeze-dried?), what other fish are in the tank, water parameters (please post values tested), and anything else you can think of to tell us.

Pictures always help, as well.

[fono15200]

No new fish recently added, it gets a 20% water change monthly (in the last month its been weekly). They are getting brine shrimp, blood worms, flakes, tubifix worms, and snails. Both of the shrimp and blood worms are freeze dried. There are 2 Gold Gourmis, a Ropefish, a Butterfly fish, 2 Sand Golbys, 2 Plecos, 2 Kilifish, and 2 Angelfish. pH is setting at 6.8, Ammonia is 0 ppm, Nitrites and Nitrates are sitting about 1 ppm, water temp is sitting steady at 76F. Trying to get pictures.

[Mzungu]

What's the specific gravity/salinity? I assume it can't be too high because the pH is at 6.8.

It's also kinda strange that you would have nitrites in an established tank...

[fono15200]

I'll have to test the salinity. I forgot to say it also has 5 plants, which are flourishing and sprouting out very well. And my mistake I meant 7.8 pH