I pulled one of our torches out and gave the skeleton a gentle scrub this evening to rid of some hair algae. Now that it's back in the tank I noticed something odd around the top. Is it a pest of some sort? We had a yellow nudibranch at some point and that's the closest thing I can think of to describe it as it's buried in there pretty good. Watching it closely it flows with the water so it's not skeleton as far as I can tell. See photo.

