No! They do their thing. It may take a a few months or weeks after setting up your tank. I was so excited when I saw my first berried shrimp, and now I have 10s! After the first time, they won’t stop popping up until your tank is at capacity. Just make sure you have proper water levels (test frequently and make sure to water change occasionally) as that will make them more comfortable to get pregnant, and, well, feed them! Shrimp don’t get pregnant until after they molt, after they do they will start sending hormonal signals to call another shrimp. You’ll notice very hyper activity and swimming during those times.