There are red varieties of dwarf gouramis and I do not believe that they are dyed. At least I have never heard that and they do not look like a dyed fish. Anyway, I looked on the Petsmart site because I know they sometimes carry 'Sunset' gouramis, but they didn't have that name. I think it must be related to this one, however, so see what you think.
Red Fire Dwarf Gourami
You may find this interesting, too. It seems that because red and blue are equally represented in the wild male gourami, breeders have been able to selectively reduce one or the other of the colors to produce many different red or blue varieties. It also states that the females are not colorful (which is why you do not often see them in fish stores). If the color was dyed, I'm sure they would dye the females as well as the males. I have cinnamon dwarfs, which have virtually no blue at all, just a pretty orange.
Dwarf Gouramis