My pair of azure damsels like to have a go but they are normally protecting eggs. My dot dash blenny also has a nibble when it gets the chance.
When I ran a shop we had a cinnamon clown who was donated and ended up in a 8ft coral tray simply because it was the grumpiest fish I've ever met. It had an anemone and would swim the entire length of the tank to protect it everytime you put your hand in the tank.
I put a sign up telling people not to put their hands in the tank but you could hear when they didn't follow that advice