It sounds like a suspension feeding cucumber to me.
Same feeding as a sea apple. Phytoplankton is what it's looking for.
Here's an article from Advanced Aquarist that explains the feeding requirements for sea apples and suspension fed cukes.:
http://www.advancedaquarist.com/issu...003/invert.htm
quote:
Until recently the ability to regularly feed phytoplankton to a reef tank was quite a feat, and involved complicated and time-consuming culture techniques to raise greenwater at home. Recently several suppliers have started to market phytoplankton for home aquaria and you can now buy live, frozen or spray-dried phytoplankton cultures to feed your reef in much the same way as you add other prepared foods. There are a number of good articles available online for how to culture phytoplankton at home (e.g., Marini 2002, Toonen 1998a), but it is now so simple to buy phytoplankton to feed to a reef tank rather than growing your own that unless you’ve got a very large tank and are using a lot of phytoplankton, most people opt to simply buy it. If you’re a real do-it-yourselfer, then it is certainly possible and cheap to culture algae at home, but you have to do it correctly or the phytoplankton can not only be non-nutritious, under some improper culture conditions, it can be downright toxic (see, Toonen 1998a). If you want to culture phytoplankton, then take the time to read some of the articles above and do it properly. Otherwise, I’d suggest purchasing your phytoplankton and let someone else do the work of culturing the stuff for you.
end quote.
And one kind word of advice, know what you're buying and what it's feeding requirements are before you buy it.
Mitch
