Same thing happend to me. I was doing a water change last month, and my mixing tank was beside my display tank. I guess the noise from the water being dumped into the tank scared one of my clowns and he jumped out. Luckly my girlfriend witnessed him trying to see if the water was cleaner on the other side, and scooped him up and placed him back in the tank. However a week before that my clown fish that I have had for over 3 years jumped through a very tiny slot between the glass top and the overflow tube for the filter. By the time I noticed he was gone, well, he was gone! My two that jumped were perc's. They will jump! :jumping: