I made a couple of shots of fiddler crabs recently and decided I wanted to identify them. It turned out to be a bit harder than I thought. Turns out there are nearly 100 different species of Fiddlers and I could only find one picture of this one.
Unfortunately it appeared on a list of unidentified species.
UPDATE: Thanks to the fiddlercrab.info site it was identified as Uca Pugilator but they are not normally so brightly colored.