Also called nudibranches
These creatures have amazing variety of shapes, patterns and colors.
How do these snails survive without shells? Why are they so varied and colorful?
They eat the stinging or toxic cells of sea anemones or coral without discharging them. The cells then pass from the slug’s digestive tract to the feathery structures on the back where they are used for defense. The bright colors and patterns combine with a sour or toxic taste so fish notice them and are repelled.
Some glow by eating luminescent algae and passing it through to their skin.