I hear they excrete toxins... when they die... i think <img src="graemlins//confused.gif" border="0" alt="[confused]" /> You have to make sure your levels are top notch because they are sensitive, and they cost $50 at the LFS. That's about it, oh yeah, they are alot like fan worms (feather dusters) because they stick these big branchy feather type things out and clean they water... they can clean up an aquarium in one day, as for snails it may take awhile... related to they cucumber and are called Medusa worms ( i think) that's it