I had a huge infestation, I got one on a Zoo rock I got from someone, and then did nothing about it. By the time I took care of it I had maybe 15-20 or so. 3 Pepermint Shrimp did the trick, gone in a week or so. Now if I ever put anything in the tank that has them again, I am ahead of the game because I have those peppermints.
David