I've had three, yes three different sets of clowns jump on me. They used to play in the output of my filter and then whoosh, straight up and out of the tank. I now have net screens over the tops of all my tanks.
I also had a yellow wathcman goby that went missing one day from my biocube, i just figured he died, got a new one etcc.,..... over a year goes by and one day I am messing in the back compartment and voila, there he was alive and much bigger than when i saw him last. lol He lived over a year back there and never got noticed. There are some incredible fish stories out there.