Grand Lido has a good dive operation. If you do the "60 ft. dive" you will probably go to Sands Club which is good for cool creatures, or The Arches which has many swim-through overhangs and pretty colors plus a Cessna sunk to start a reef. Bloody bay itself is a good snorkle site & has some diving. You may also do The Throne Room where you drop down a hole and swim out - pretty cool. There are other areas but these are most common.
The diving around Negril is good but not outstanding. My list of creatures includes, nurse sharks, many barracudas, several reef squid, many small skates, good sized southern rays, electric ray, octopus, puffers, burrfish, banded shrimp, arrowline crabs, large crabs, many small and a few big morays, several seasnakes, plenty of turtles, lots of french grunts & creole wrasses, etc. The coral is in good shape most places and some really good colors, most under overhangs. Have fun!