Thanks Mola. Do you know what use they in an aquarium? I've got about 10 that I can see now. They make a small mound out of the gravel, and the only part sticking out of the gravel is the tentacles. How am I suposed to clean the gravel without sucking them up to? Are they worth the trouble to try to save while cleaning? How big do they get? Are these little guys a big deal (common, uncommon)? I only started seeing them in the past month or so. Having not added anything but a few fish about 3 months ago, where did they come from? Info Info Info :notsure: . Thanks guys.