I had a serial killer mis bar clown. It was my first saltwater fish so I was partial to it. I have no doubt it was responsible for killing every other fish I ever put in the tank. The first couple I wasn't sure at first but then I caught her in the act. Once the lights went out she went on the hunt. Came home late one night to her checking a tank mate into the corner in the dark. Her victims included in order: Cleaner shrimp, Orange Diamond Goby, Green Clown Goby, Royal Gamma (this one put up the most fight, till she broke his back dead in the center of his body, lived another couple months like that but rarely came out of his rock again, and finally my prized Pygmy Pacific Angel fish. I wouldn't put it past the clowns at least participating in the goby down fall.