Just did a water change and all of my brittle stars started coming out of the rocks. Normally their legs stick out of the rocks, but I rarely see their entire bodies. I started to freak out, thinking I had seriously screwed something up. But then I noticed they were taking turns lifting up their bodies and releasing sperm into the water. My clown fish spawn all the time, but this is the first time anything else has spawned in my tank. Pretty sweet.