Mysterious Creatures Sea Monkey Breeding Set - That No! Sea Monkey is back! Living fossils come back? Really born with just water. Wonder & Science! It will grow up to approximately 0.8 inches (2 cm). Your child will be born! Easy for anyone! Let your Simonkey be born! 1. Fill the tank with tap water and [1] Put the pack. More than 24 hours 2. Fill the sea monkey eggs ([2] pack). 3.Feed the bait ([3] pack) every 7 to 10 days. Recommended Age: 6 years and up.