Hydatina zonata

Image courtesy of Lawrence Neal
Koh Libong (Libong Island) in the Andaman Sea (eastern Indian Ocean)
Image courtesy of Lawrence Neal
Koh Libong (Libong Island) in the Andaman Sea (eastern Indian Ocean)
Hydatina zonata in search of prey

Hydatina zonata (Lightfoot, 1786)

This is a very sexy looking bubble snail. Its bright color and stripes should warn any potential predator that it is toxic. Toxic you say - how can that be? Well simple - this species feeds on cirratulid polychaete worms and incorporates secondary derived toxins from the prey into its tissue for it own defense.

The mantle tissue is bright red in the majority of specimens with white ruffled edges. The shell is brown with numerous elongate lines and with one or more white spiral bands. These bands are outlined with dark brown lines in some specimens like Lawrence's here.

Lawrence's photogaphy of H. zonata is nothing short of spectacular!

This species is widespread throughout the Indo-Pacific.


Lightfoot, J. 1786. A Catalogue of the Portland Museum lately the property of the Dowager Duchess of Portland, Deceased: which will be sold by Auction. 194pp, Plate 1. London.

Dave Behrens
Sammamish, WA 98074
Jul., 2021
Send Dave email at davidwbehrens@gmail.com

Lawrence Neal

Lawrence Neal is a British freelance professional based in Bangkok, Thailand. He escapes the city for coastal waters in the south of the country whenever time and global pandemics permit. Apart from diving and underwater photography, Lawrence enjoys travel, trekking, landscape photography, fitness and biohacking.

He currently uses a Nikon d850 with a 105-mm macro lens, a pair of Backscatter MF-1 strobes and assorted wet lenses.

Lawrence's notes on his encounter with Hydatina zonata.

"... It was encountered off Koh Libong (Libong Island) in the Andaman Sea (eastern Indian Ocean), Trang province of southwestern Thailand. The site is mixed sand and sediment, at around 14 meters depth, with some Halophila sea grass. The slug was continuously on the move except every now and again it would pause and dive into the sand (seen above), presumably in search of prey..."

Lawrence Neal
Bangkok, Thailand
Mar. 2021

Send Lawrence mail at lorenzo_n@yahoo.com

Attention all you Sluggers, and you know who you are!

The NSSI 2nd edition is now available in ebook PDF and book form . The hard back version will become available Nov. 1st. Both will cost $65 (individually).

You will need to jump through a few hoops to get the electronic version as pdf distribution is protected by Adobe ID!! Please read the following to enable reading your electronic purchase!

This new 2nd Edition is updated and reorganized, including 185 new species. Among other features, the new edition includes additional photographs of species, an identification key, and an up-to-date classification reflecting the latest evolutionary relationships. The Indo-Pacific represents the largest expanse of tropical ocean in the world, stretching from the Indian Ocean coast of southern Africa and the Red Sea to the central Pacific of the Hawaiian Islands, Easter Island and the Marquesas.

This region supports the most diverse marine fauna of any place in the world for most groups of marine organisms. The nudibranchs and sea slugs are no exception to this rule; there are about 3,000 described species of these organisms in the world and at least 40% of these have been found exclusively in the Indo-Pacific tropics. This book illustrates 2,138 Indo-Pacific nudibranchs and sea slugs, including many undescribed species.

From left to right, Terry Gosliner, Angel Valdes, Dave Behrens La Jolla, Calif.

Send Dave email at davidwbehrens@gmail.com

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