According to my fish book there are roughly 500 species of fish that live in the Caribbean.  In terms of numerosity, based on the various islands that I have been to, grunts of various varieties are by far the most common.  Over the years I have shot quite a few groups of grunts.  Some of the groups have been had hundreds of individuals, other have only had a dozen or so individuals.  Grunts are pretty but they are not my favorite fish.  

Schoolmasters are also interesting looking fish.  I have found them in a variety of dive sites and they tend to be fairly curious and inquisitive about divers.  So under the right circumstances they make interesting subjects to photograph. 

Nevertheless, if I were to pick one type of fish that I think is the most interesting to shoot in larger aggregations, I would have to say it is the pork fish.  Yellow and white with black highlights makes it a very interesting fish.  In many places in the Caribbean, pork fish appear to be relatively rare.  But, in the Riviera Maya on the east coast of Mexico there are still quite a few sites that have relatively large schools of pork fish.  In Playa del Carmen and at the underwater museum at Isla Mujeres are the two places that I have seen the most pork fish.  And, if I can see grunts, schools masters and pork fish swimming together it is a good day.