The Smallmouth Grunt is in the family Haemulidae. They are numerous and widespread, with about 150 species in 19 genera, found in tropical waters around the world. They are bottom-feeding predators, and named for their ability to produce sound by grinding their teeth. They require a large tank with plenty of ledges to hide under. They are not considered to be reef safe but only because they get big and will mess up your reef set up, not because they eat coral. Smallmouth Grunts will eat anything and can be tank mates with almost all fish.