Planarian (Flat Worm) - Planarians are small freshwater flatworms that range from 3-12mm in size and have two eyespots that allow them to move away from light. They have three tissue layers and are carnivorous, feeding on other organisms and dead matter. - Planarians can reproduce asexually through budding or fission, or sexually by exchanging sperm. They are found beneath rocks and debris in freshwater environments around the world.