Reef Stories

Nudibranchs &

Sea Slugs

Nudibranchs & Sea Slugs

Index

Sea Slugs

Side-Gilled

Umbrella Shells

Head-shield Slugs

Pteropods

Sap-Sucking Slugs

Sea Hares

Nudibranchs

Phanerobranch Dorids

Cryptobranch Discodorids

Cryptobranch Chromodorids

Radula-less Dorids

Arminids

Dendronotids

Aeolids

Nudibranchs are found in all areas of reefs, on seaweeds, on the ocean floor and even swimming in the ocean currents. Some feed on other nudibranchs, others bryozoans, jellyfish, corals, sponges, ascideans, fish mucous, and seaweed.

Those that feed on animals with stinging cells, can absorb the stinging cells without triggering the firing mechnism. Any predator is not so protected and in biting into the nudibranch, causes all the stinging cells to fire their poisonous darts. Sponge eaters absorb and concentrate the sponge toxins in their bodies.

Those with stinging cells and toxins are often brightly coloured to warn of their danger. Those living on seaweeds are often extremely cryptic. Sediment living species often live within the sediment and only come out at night to feed.

The classification followed here is that in "Nudibranch & Sea Slug Identification", by T. M. Gosliner, A. Valdés & D. W. Behrens (2nd edition, 2018). Images with a species number are detailed in this guide. A review of the guide can be found on the reviews page on this web-site. Many details of sea slugs and nudibranchs can be found there and online in the Slug Site.

Side-Gilled & Basal-Shelled Sea Slugs

These groups are closely related to nudibranchs. Many have small internal shells, which may disappear in the adults.

Some Pleurobranchus species grow up to 60cm long. Many produce acidic secretions as a defence mechanism.

Help Save Reefs!

The organisations that work to protect coral reefs and our oceans need as much support as they can get. Check out:

Sea Shepherd
Conservation Intl.

If you are a diver, and especially if you are an underwater photographer, donate. If you do nothing, there will be nothing to dive on and nothing to photograph.

Other groups

These are suggestions, but not endorsements of the suggested organisations. It is your responsibility to review and check the charities you wish to donate to.