Molluscs • Wildlife

Nudibranch

Colorful Slugs of the Sea

© SSI-Peter-Schinck

One of the most fascinating creatures of the sea, these small but mighty jelly-bodied, shell-less mollusks are part of the sea slug family. Nudibranchs inhabit ocean waters throughout the world, from the Southern Ocean to the Arctic and everywhere in between. Depending on the species, adult sizes can range from 0.25 to 12 inches. These soft-bodied gastropods derive their name from the Latin word Nudibranchia, meaning naked gills, which is why most have feathery gills and horns on their backs.

Nudibranchs are famous for their extravagant coloration and ornate patterns, making them a favorite sighting amongst divers. Three thousand known species of nudibranchs live in all saltwater habitats and depths from the intertidal zone to over 700m (2,300ft) deep; however, the largest variety resides on shallow, warm reefs. As benthic animals, these beautiful, oblong-shaped invertebrates are usually seen crawling along the substrate, grazing on algae, coral, anemones, sponges, and more. Check out the map below to see where you can find your favorite nudibranch species.

Popular dive sites

Gasoline Station

Gasoline Station

5 Logged dives • 7 Sightings This Dive site located on the mainland just out of Manado Bay, just off the southern tip of Sulawesi sea. This is a great site for finding interesting bottom dwellers.
Indonesia
Big Fish Wall

Big Fish Wall

23 Logged dives • 20 Sightings Starts with a sandy coral slope, then turns into a wall at 40 to 50 meters. Best dived in moderate current, right shoulder to the reef. Often the dive is finished on the reef top at Big Fish Country or in the channel.
Indonesia
Tanjung Bakau 3

Tanjung Bakau 3

24 Logged dives • 20 Sightings Five minutes boat ride South West from Nabucco Spice Island Resort. Marginal reef with coral garden which slopes down to sandy seabed from 25 metres.
Indonesia
Sali Bay East Freestyle

Sali Bay East Freestyle

11 Logged dives • 9 Sightings 20 minutes boat ride from Nabucco Spice Island Resort, at the eastern end of Sali Bay. Strong current running around a headland. The undulating sea bed can cause strong vertical currents in places.
Indonesia
Tanjung Neraka

Tanjung Neraka

32 Logged dives • 22 Sightings 5 Minutes boat ride from Kusu Island. This dive site sits on a corner of Bacan. Depending on the current there are actually 2 divesite - 1 to the north and 1 to the south. Slope with good coral coverage. Can have strong currents.
Indonesia