This is the lionfish. They have come from the Pacific in the holds of ships and now they are an invasive species in the Caribbean. They have no natural predators. They have another surprise. The ends of the "feathers" are extremely poisonous. They have venom that can kill a man.
I have taken to shooting them with my Hawaiian sling. They are slow moving and easy to hit. When I do miss, they fold up their plumes and dart away. They are quite a skinny fish with their feathers down.
When I do pot one, I carefully take it to the beach and bury it on the beach. It turns out that I am wasting some real good tasting fish.
The way to safely clean the fish, is to have thick rubber gloves and cut off the appendages with a pair of scissors. You have to be careful, because even when the fish is dead, the spring-loaded nemacysts are still capable of delivering a lethal dose.
I went to a function of the Bahamas National Trust, and they were serving lionfish fingers. They were delicious. They tasted as good as grouper.
This lionfish was photographed by Becky at Atlantis.