The sand channels on Little Cayman are often populated with colonies of Brown Garden Eels (Heteroconger longissimus), like these two.  These things are very difficult to photograph, because they retract into their holes whenever you get within about 10' of them.  But I find them to be fascinating little creatures.  They always lean into the current, no matter how slight, and that is one of the visual cues a diver can use to determine the current direction.  These little fellows are 15" long and space themselves in the sand in a very regular pattern:  they are just close enough together that they can make physical contact with each other if both partners are so inclined, but NOT if one of the pair has a headache tonight!