I've been getting this stuff in my Fluval Evo 13 back chambers for a while now. All three of them. This stuff kind of grosses me out because it looks like sunburned skin with hair follicle goose bumps . Lately it has been spreading into my display and is growing rapidly on my little rockscape. Once in a while, I'll search for what type of sponge it might be and today after falling down wormholes I figured out it is - Aplysilla rosea. But no forums talk about it. Does anyone here have it and how do you feel about it? Any info appreciated. Below is a screenshot from the world wide web but I can take photos of my situation when I get off work.