Opistobranchs are a large and diverse group of marine gastropods. They include several types of sea slugs: sea hares, sea angels, sea butterflies, and many families of Nudibranchia. They exist in an impressive diversity of sizes, colors and shapes and are distributed in sea waters all over the world. Species exist that are adapted to different climates, salinity, or depth. Help us gather information about these maginificent creatures by adding your spottings here in this mission.