Funy story, I took a gamble and got my GSMs from two separate tanks at a local lfs. one was slightly larger than the other... As soon and I mean as soon as they hit the DT water, the larger of the two clamped down on the smaller ones right fin and took him for a death roll 24" to the bottom of the tank. As soon as the larger one let go, they've been a happy couple ever since.. LOL.. These creatures are hilarious. Definitely one of my reefs memorable moments.