Cucumber?

I have a 55gal and was looking into getting a sea cucumber. I want one that filters sand. I was trading corals once and saw one that was really neat. All of the ones I keep reading about filter the water and not the sand. Any species ideas?

 

As far as I know sea cucumbers spend their time inside the live rocks filter-feeding, and rarely come out.

 

I know of some that do that. However, the one I saw was brown an very much out. You couldsee little sand pellets it left behind. It was really neat. Can't find it anywhere though.

 

The tiger tail cucumber and the black atlantic ones will ingest sand, and excrete 100% clean sand.

I have one of each in my 200g.

Both are easy to find for sale. The purple and black ones filter the sand as well.
http://www.liveaquaria.com/product/prod_display.cfm?c=497 502 707&pcatid=707
Saltwater Aquarium Inverts for Marine Reef Aquariums: Sea Cucumber, Tiger Tail

 

cucumber

The pink ( I think hawaiian) cucumbers eat sand. Had one for years before.

 

I have two in my 150g and both filter the sand and excreet clean sand pellets. However from what I have read be careful because if they become stressed I believe they can excreet a toxin into your tank.