Three Parts:Getting Everything You'll Need to Raise Sea Monkeys Hatching Sea They can also live up to 2 years with little attention. . How long do they live?. Q. I have tried to keep Sea Monkeys twice but they 1. blow into the tank with a long straw for about 2. How long do they live? The sea monkeys will live up to two years. How big will sea monkeys become? So big that they will swallow your house - only kidding!.