There are two main sources of dwarf gouramis. European or asian origin. Unfortunately the hardiness has been bred out of the asian line in pursuit of beauty. This means they are susceptable to the smallest problems within the aquarium ecosystem. They are likely to have internal parasites, and will just as often die. I tried my luck with three, they all died the same way, all seemed lethargic for a while, then a wound like growth appeared, got worse and they died. It is a real issue for me, it really makes me mad, especially as I can only find asian strain here in Australia. We have Chocolate Gouramis too, which are suppose to be far more vulnerable, but we have found them to be very hardy indeed. Especially in comparison to the Dwarf varieties.
Consider it dead. I'm sorry.