👉 Nudibranchs are small, aquatic invertebrates that primarily live on the surface of water bodies. They have a unique adaptation called a "nudibranch shell," which is composed of a hard outer layer and a soft inner lining. These shells are often used for protection and defense, as well as for feeding purposes. Nudibranchs also exhibit various forms of locomotion, including swimming, walking on the surface, or crawling beneath water.