Here is a little info i found on them. My main way of discribing groupers is a swimming mouth.

they tend to be rather relaxed till food hits the water. I have never had one due to there size and how fast they grow. Hope this helps.
Common Names: Blue Spot Grouper, Peacock Grouper, Argus Grouper
Hawaiian Name: Roi
Scientific Name: Cephalopholis argus (Bloch & Schneider, 1801)
Source Info: Debbie & Stan Hauter, and Fishes of Hawaii by Spencer W. Tinker
The Peacock Grouper is one of a number of fish species introduced to the islands of Oahu and The Big Island, from Moorea in the Society Islands (where they were known as "Roi") beginning in 1956 as a potential food fish for the inhabitants of Hawai'i. Since that time, they have spread throughout the island chain. As a food fish, the meat is white, fine-grained and very tender, much like Ling Cod.
This shy, beautiful carnivore can be found anywhere from inside the reef to depths beyond 100 foot depths, anywhere there is a "puka" (Hawaiian for "hole") deep enough to hide in.
This fish can grow to a length in excess of 3 feet, and therefore requires a large tank environment.
In captivity, the Blue Spot Grouper settles quickly into a confident, lazy attitude as long as it has a place to dart into when startled or feeling threatened. We wouldn't recommend placing small fish in the same tank, unless you plan on losing them, as this fish is a natural live food source predator. It is a good fish to keep in a large predatory fish tank with Lionfishes, Hawks, Puffers and Triggers. The Blue Spot Grouper will readily eat dried, frozen or prepared meaty fares and crabs, shrimp and other crustaceans. If you are a dyed in the wool naturalist, drop a few live feeder fish into the tank and watch your spotted prize revert back to its wild natural hunting instincts in a heartbeat.