I picked up a tuxedo urchin because the partial crash a few weeks ago caused a serious algae outbreak in my tank. I want the rocks to be cleaned up before the transfer, so I figured an urchin could wipe out the algae problem in a couple weeks. Once all the algae is gone, I'll take the urchin back to the store so it doesn't starve. Such a cool critter! I'm enjoying watching it and wish I could keep it long term. Here is a quick photo and video of it on the tank glass.