Strange goo in Crayfish tank? I noticed an excess of this weird, while, stringy stuff sticking to the walls of his tank. It looks like some sort of plant or algae, but white-ish. When I took a picture with flash (this is under a large rock type habitat), then it flashed green. I noticed more this morning, but until last night I hadn't noticed anything. It's bubbly and looks extremely slimey. There are bits floating around the tank too, in areas. What is this? Is it safe? Is my Crayfish producing it or is it something that could make him sick? As I said, I couldn't get a good picture.