I've been trying to post this for a while but failing cos Blogger went weird (which is also why I've not responded to comments). Anyway in keeping with recent crustacean based posts here's one of my all time favourite animals (and one of my favourite photos).
This spectacular little chap is Periclimenes pedersoni. It's a carribean cleaner shrimp that lives in anemones (the little spirally things in the back are curlycue anemone tentacles). This image is much bigger than life size for this species and you can only really appreciate their detail with a magnifier or having taken photographs. Their size and transparency should make them difficult to spot but their habit of living in anemone's means informed divers can find them easily (and impress those not so sure what to look for).