Sea slugs can be divided into many types according to their living environment and geographical location. The scientific name of the sea slug "Chromodoris bullocki" was photographed while eating. This sea slug is distinguished from other species by its distinctive bright purple skin and orange gills.

The sea slug scientifically known as "Chromodoris" can often be found in the South Pacific. The scientific name of this sea slug means nudibranch. Published in the June 2008 issue of National Geographic magazine. The transparent 1.7-inch-long sea slug, Phyllodesmium iriomotense, feeds exclusively on coral. This species is a rare colorless nudibranch. The brightly colored sea slug "Chromodoris bullocki" was photographed in Indonesia's Lembeh Strait. It breathes using gills on its back.

The color of the sea slug, whose scientific name is "Nembrotha kubaryana", varies. This sea slug is black, but others have distinct green markings, while others have orange markings. It eats green mixtures such as the seaweed "Eudistoma olivaceum". The sea slug, Tambja verconis, was discovered near New Zealand. It lives on bushy plant-like bryozoans (Bugula dentata).

A close-up of the sea slug "Hermissenda crassicornis", whose body color is milky white. It is often found on docks and piling sites. The sea slug, whose scientific name is Phyllidia varicosa, occupies the Indo-Western Pacific zone, which is a marine biogeographic zone that stretches from the west coast of the Indian Ocean across the eastern ends of the Pacific Islands, and is often used in the Indo-Pacific zone. The area is composed of tropical (subtropical) waters starting from the east coast of Africa, including the Red Sea, from the southern half of Japan in the north, to the northern half of Australia in the south, and to Easter Island in the east. The basic colors of this sea slug are black, blue-gray and yellow. Nudibranchs are found in Indonesia and surrounding areas.

The sea slug scientifically known as "Notodoris minor" is a larger and brighter species. Unlike other sea slugs, it does not have the classic soft and delicate body, but has a hard and rigid body. This makes it look more like a sponge than a sea slug. The scientific name of the sea slug "Phyllidia ocellata" has no gills on its back, which is a unique feature of this species.