Yep...hydra....that is what I posted about a few weeks ago Amy! Right when I read your heading I was thinking....Hydra....those nasty little buggers. I still have them in my shrimp tank, but am planning on redoing that tank soon with sand and will get rid of them! Not because of the sand, but because I am going to clean the tank as well. My 11 year old daughter spotted a small hydra on a plant in my 29g yesterday, but I don't have any small fish or shrimp in that tank so I don't worry as much. When I see them in my shrimp tank, I usually scrape them from the sides or reach in and pinch the ***** out of them to smush them!