Nudibranchs are soft-bodied marine mollusks commonly known as sea slugs. With nearly 3,000 described species, nudibranchs come in a diverse array of colors and patterns that have inspired jewelry design and earned them the name "gems of the sea." While colorful and diverse, nudibranchs have specific dietary and habitat needs that make them difficult to keep in aquariums, so the best way to observe their fantastic forms is in their natural ocean environment.