Aha, I think (just think) that the second Leopard Wrasse is still alive. A few minutes ago I was just walking past the tank when I noticed a cloud of sand being blown up. It's was the same as when a Wrasse decides to dive under the sand. I did a quick check and all of the normal crew were swimming about, so it was none of them. I can only guess that the Leopard had come up for a look and me going past the tank spooked it again to dive under the sand.