Hi everyone, I'm running a 29 Gallon Reef tank with some fish and your basic corals. The equipment for this tank is nano protein skimmer, ehiem filter, coral life 150 watts and 2 maxijets, I am not using RO/DI water yet I am in process of getting it, but I am using poland spring water for now untill then. So I've notice today on one of my clown fish that there's alittle bump on his skin and the color is white and looks like a pimple ready to pop. I'm really thinking that the reason for this taking place is cause I had bought some fish from PETCO and 2 fish from there that I bought had died. I'm really worried about them and I don't want anything bad to happen!! what can I use to cure this problem? what are the steps? would the other fish be ok? This is my first tank so like I said I'm really worried about these little guys. Thank You!