I was looking at my aquarium glass and i Noticed these green things with a lot of legs and researched and it was. Hydra. I don't think I have too many but I want to get rid if them quick. I've heard Molly's eat em but I'm not very sure how fast they will eat them. So if I do have to use medication what medicate do I use? It is a 75 gallon with 11 polypterus so what would the dosing be.