The spot (that I think you mean) is on the glass. But do you maybe know something I can do to maybe boost their immune system just in case that they have some sort of illness? Because i personally think that (especially the golden dust) has a pretty... Let's say not so normal looking finOn the orange one i can see a white spot on the tail and i think there is another smaller less noticable one above it? Maybe its from the aquarium glass but if its on the fish i dont really know what it is because its too big for an ich spot