A better description -- the algae is not flat on the rock, it is a gorgeous raspberry color, and it is about an inch long, and about half an inch high, with a ruffled edge. Protruding from all over the ruffled edge are little nearly opaque hairs. They do not come from one location only. There are smaller raspberry-colored masses that also have these hairs on them. I have a sally, and so far, she has not been too interested in this stuff at all.