ok So I got two black female swordtails from the LFS on Saturday, on monday they both showed signs of ich (small white spots) but it was minimal I've only seen maybe 5 max spots on each fish, but on top of that one of them had this weird white spot (much larger then the few ich spots.) could it be a concentration of ich parasites? I've attached some pictures of the female with her spots the spot is at the top base of her tail. I'm treating the tank right now with formalin (37% formaldehyde) 2 drops per gallon every other day (as recommended on label) this is my second day of treatment. what can I do for this other spot though? thanks for your help, here's the pics: