Grouper have several sets of teeth, placed in the mouth to act as raspers or holding teeth. The fish gulps down its prey using these raspers to prevent the smaller fish from escaping. The teeth are not used to tear or slash, as with barracuda or sharks.
Personal experience with a large Nassau grouper (“Herbie”) on a trip to Stella Maris in the Bahamas resulted in the loss of skin from the back of my right hand and fingers, followed by a severe infection. “Herbie”, with other groupers not quite so large, were accustomed to being fed at “Grouper City”, a dive site off Long Island. I was put into the water without food for them and unluckily for me, without my gloves. While beating off another grouper in front of me, “Herbie” took my entire fist and forearm into his mouth and as I struck forward, his raspers ripped off and abraded considerable skin of the back of my hand.
The jewfish is a member of the grouper family and some can get as large as 800 pounds, and can easily endanger a human, although I know of no reports. This fish is totally protected in Florida waters.