The swim bladder is a third-party organ for Creatures 3 and Docking Station creatures, developed by KittyTikara in the Astro Tetras. The swim bladder allows swimming females to lay eggs like a land-bound Norn would. Over the course of their pregnancy, females will get tired and will temporarily lose the ability to swim. Once they lay their egg, they will be able to swim again. It is named after the swim bladder organ in fish.