Marine snails are common coral reef mollusks found on reefs and in sand plain and seagrass meadow habitats as well.
The vast majority of these animals are herbivorous slow-moving benthic grazers with a one-piece shell, as exemplified by the highly-prized Caribbean conchs, now badly overfished throughout the region for both their meat and shells.
Most of the smaller species are well camouflaged or well-hidden, spending most of the time safely concealed beneath the sand.
Not all coral reef mollusks are herbivores. For example, a common octocoral predator of Caribbean reefs is the flamingo tongue (pictured left). This colorful carnivore is often found in plain sight grazing on sea fan polyps.
Some coral reef mollusks – particulalry gastropods – make excellent additions to marine aquariums, as they help keep unwanted algae in check.
By far, the most colorful (and popular with marine aquarium owners) of reef-dwelling gastropods are the nudibranchs (see photo, left).
These are a type of marine snail that lacks a protective shell and is often cloaked in brilliant colors that serve to warn predators of their foul taste or poisons.
They are not uncommon coral reef mollusks, but many species have cryptic coloration and are therefore nearly impossible to be spotted by divers.
On Indo-Pacific reefs, predatory snails called cone shells contains species that have the capacity to inject a neurotoxin that can be lethal to much larger animals, including humans.