I have a tank with 2 (until recently 3) drawf gouramis and 2 female bettas. I recently introduced one of the bettas after saving it from a cup. One dwarf just died within about 2 days; was just all of a sudden listless and barely moved. Now it seems to be happening to another dwarf; his gills are kind of pinkish and he just sits there. However through all this my bettas are completely fine. Is this that dreaded ick?