I have had a mantis shrimp in the past - found at night with a flashlight with red lens cover - after I noticed very stressed fish, feather duster heads cut, etc. Currently, I have (so far) found several varieties of small snails, a chiton, aiptasia, very small feather dusters and other types of weird worms, bristleworms, small asterina starfish, and some weird, white, cottony - spongy looking stuff growing on the LR. This spongy stuff is very brittle and breaks easily, but seems to grow back. Anyone know what it might be?