Cool pic of a Thor amboinensis! Mine like to hang around their Phymantus anemone, but will sit in the Condylactis too. I hoped they would live in my Ricordeas, but they never did.
I'm not much for scientific names of inverts (don't have a good atlas), but I think the harlequin shrimp you might be referring to is generally the same pattern, but is white with pink splotches on it, and has frilly claws. It eats only starfish, and is awesome to keep in pairs if you have access to a lot of starfish (had a pair, and fed them frozen chocolate chip stars, until I couldn't find anymore, and then they died off
Its a thor amboinensis, common name broken back or sexy shrimp (it waves its butt fluidly most likely to mimic the tentacles of the anemones it lives in). I'd really like to get a mpeg movie of him, they're just so cool!
Thats weird, i still cant see it...
I'll get a good pic of my harlequin too, they look very different. Harlequin shrimp have big plate like appendages on their front legs and are usually white with brown spots.
Oh BTW, i don't have (or recommend importing/keeping) any anemones in my tank so i guess the ricordea's the next best thing! I have another smaller one that hides behind it.