your fish
Take a good look at the photo below.
Circle A:
Notice this doesn't go past the fin. The blotch looks like it may be a result of the fin scraping along the side; tearing away at the scales little by little and lightening the pigment. His belly is too fat and there may be damage to the fins allowing the pointed bones of the fin rays to poke the side of the body, scraping at the scales as he swims. A normal appearance of the stomach (flatter and more even and smooth contour with the rest of the body), the fins wouldn't have interference from the extended bump of a bloated belly. Damage to the fins may have something to do what is described in Circle C and D.
Circle B:
Same as above but near a lighter pigment. These areas might be 'dry' or lacking slime because of the irritation. This is where the Stress Coat helps. It's like a band aid giving the fish a layer of protective slime.
Circle C:
This makes me think of it possibly being ich, which leads to...
Circle D (and beyond the circles):
This looks like a population of little critters (parasites) attached to the fish.
Along with the half dose of Melafix and Stress Coat, add half a dose of a general external parasite medication. It may take a little longer to clear up being half a dose, but you want to avoid over medicating/treatment.
Now about the big belly. Where is it coming from? Internal parasites? Blockage? Or overfeeding?
Internal parasites generally show some type of wasting away, especially intestinal parasites which rob the fish of it's nutrients. They will thin out with or without a bloated belly. Another good sign of these parasites is if the fish poops red or white or clear material. This doesn't seem to fit the animals appearance though and wouldn't jump too soon on any internal parasite meds.
Blockage usually comes from too much meat protein in the diet. The fish will have difficulty passing waste, if be able to at all. When was the last time you've seen him pass waste? A good diet with lots of veggie proteins will help aid the digestive system from becoming blocked. Frozen peas, thawed and peeled from their shells make a good laxative.
Overfeeding is quite easy to do especially if you go by the directions on the backs of fish food packages. Go figure.
For a dwarf gourami, no more than two to three minutes worth of food per day, best divided into three or more feeds throughout the day. Meaning if you feed four times a day, each feed should be what the fish can consume in 30 to 45 seconds. Good to skip a day or two in the week and let the fish pick around the tank for any left overs.