If you want to fuck up a seafood restaurant, throw a penny in the lobster tank. Copper’s bad for crustaceans and a penny will wipe out a whole tank. At a place where I worked when the owners were being complete dicks one of the cooks would surreptitiously drop a few pennies into the lobster tank, wiping out the entire lobster population. It was usually blamed on a little kid who probably thought it was some kind of wishing well, or fountain or another bit of water where people throw change. It’s called Shit Chef for a reason.