I don't know of anyone who's had that problem. There are more people who can't seem to keep them alive. I bought 3 on a whim because they were such cool little critters...and then two of them died within a week for unknown reasons (probably because I am/was cycling the tank) but one of them is still alive and kickin! If you had a problem with overpopulation of the shrimp all you'd have to do is catch some and bring them back to the store, or put them in a tank with bigger fish...bigger fish will munch them down as snacks!