There's a fungal sapro. Not the bacteria. But it usually needs some kinda dead matter to feed on...its def some kind of mold though.
I dunno...the tank isn't cycled. I noticed its growing on the same type of heater suction cups in my 20g that I'm cycling right now too. I think its already in the water but who knows why its growing on that. :) I'm not sure why replacing the cups is necessary...bleach and hot water should clean those and its already in the water I guess since its in both tanks. Everything is brand new....really weird cuz its not growing on any of my cycled tanks suction cups LOL. I read that water mold is encouraged in poor water conditions and since i've got the tank cycling...that qualifies. I'm not gonna worry about it too much :)
^that is positively gross!!!!Try taking off the cups and just kinda "float" the heater, but make sure that its sumberged properly. Clearly the cups are the issue, see if there is another way to hold the heater in place