Found this guy hanging out on my filter sock this morning. Looks like a small snail. Has a hard shell that has a spiral in it, but when viewed from the side the shell is mostly flat and just rests on the back of whatever this is.
Good to know. Wondering how it got in. I’ve added some corals lately but dipped them with s bayer mix. The GSP was attached to a tiny piece of rock, so maybe it hid out there.