Favorite Sea Slug Poll — Top 10 Results

Thanks everyone for voting for your favorite sea slug. Over three days we gathered about 200 votes across 96 species — the results were diverse and full of surprises. Here are the rankings.

1st: Aoumiushi (Hypselodoris festiva) — 16 votes

Hypselodoris festiva (A. Adams, 1861)

The classic Aoumiushi takes the top spot — a strong showing. It's only found in temperate waters around Japan, and the numbers seem to be slowly declining. Let's take care of them.

2nd: Mizore-umiushi (Chromodoris willani) — 12 votes

Chromodoris willani Rudman, 1982

A surprise contender at 2nd. The shimmering rhinophores and gills are beautiful. In Japan you'll find it in the Izu Islands and Okinawa. In southern seas it's often seen clustering on its host sponge.

3rd: Shinderera-umiushi (Hypselodoris apolegma) — 11 votes

Hypselodoris apolegma (Yonow, 2001)

3rd goes to Shinderera-umiushi ("Cinderella" in Japanese) — a perennial favorite. Many look-alikes exist, but the distinctive dotted/reticulated skirt pattern makes it easy to identify. Also found in the Izu Islands and Okinawa. It grows quite large, with a striking presence.

4th: Aomino-umiushi (Glaucus atlanticus) — 10 votes

Glaucus atlanticus Forster, 1777

4th is Aomino-umiushi, a pelagic sea slug that feeds on Portuguese man-o'-war and by-the-wind sailor and spends its whole life at the sea surface. This year they kept washing up near Hayama on southerly-wind days, and many people got photos.

4th (tie): Hohobeni-moumiushi (Costasiella sp.) — 10 votes

Costasiella sp.

Tied for 4th: Hohobeni-moumiushi. It became briefly famous for looking like Shaun the Sheep. Not found in Japanese waters — you'll see it in Indonesia and Malaysia. Many similar undescribed species exist in the same group, and the taxonomy is still unsettled. Full-body shots are usually needed to identify sea slugs, but this species really calls for a face portrait.

6th: Gomafu-biroudo-umiushi (Jorunna parva) — 6 votes

Jorunna parva (Baba, 1938)

6th place: Gomafu-biroudo-umiushi, nicknamed "Goma-chan". The front view is often compared to a rabbit's face. Fairly widespread throughout Japan.

6th (tie): Zougeiro-umiushi (Hypselodoris bullockii) — 6 votes

Hypselodoris bullockii (Collingwood, 1881)

Tied for 6th: Zougeiro-umiushi — a personal favorite of the SEASLUG.WORLD operator. It was once lumped with Shinderera-umiushi and others as a single species, but has since been split extensively… making it quite hard to tell which is the "true" H. bullockii anymore.

8th: Udefuri-tsunozaya-umiushi (Thecacera pacifica) — 5 votes

Thecacera pacifica Bergh, 1883

8th: Udefuri-tsunozaya-umiushi, nicknamed "Pikachu". Widespread in Japan where it also grows fairly large, but rarely seen overseas. As a result, other Thecacera species are often called "Pikachu" in non-Japanese communities.

8th (tie): Bobusan-umiushi (Goniobranchus roboi) — 5 votes

Goniobranchus roboi (Gosliner & Behrens, 1998)

Tied for 8th: Bobusan-umiushi. The distinctive crepe-like (or omelet-like) pattern is unmistakable. Both the Japanese and scientific names honor "Bob-san" (Robert F. Bolland). Apparently Bob-san first found it at extraordinary depth, but lately it's commonly seen at normal diving depths in Izu — curious.

10th: Akaten-iro-umiushi (Ardeadoris cruenta) — 4 votes

Ardeadoris cruenta (Rudman, 1986)

10th: Akaten-iro-umiushi. I thought it would be more popular — a sea slug with a simply beautiful skirt.

10th (tie): Hiodoshi-yubi-umiushi (Bornella anguilla) — 4 votes

Bornella anguilla Johnson, 1984

Tied for 10th: Hiodoshi-yubi-umiushi. A surprising favorite — dragon-like, photogenic in head-on shots, and it swims. A stylish sea slug.

12th (3 votes each)

Micromelo undatus (Konshibori-gai), Sagaminopteron ornatum (Murasaki-umikochou)

14th (2 votes each)

Migaki-budou-gai, Neon-moumiushi, Hanabi-moumiushi, Hiroumiushi, Renge-umiushi, Sarasa-umiushi, Kanokouroko-umiushi, Tengu-moumiushi, Caramel-umiushi, Midori-ryuugu-umiushi, Mukade-meribe, Fujinami-umiushi, Miyako-umiushi, Kikamoyou-umiushi, Buchi-umiushi — and others.

1 vote (many species)

A long tail of species received one vote each — from various Umikochou (bubble snails) and Hana-saki-senhime to species honoring well-known taxonomists (Coleman's, Bergh's, and others). The full list is too long to translate here; please refer to the Japanese version for the complete enumeration.

That's the full ranking. Where did your favorite place?

On SEASLUG.WORLD, we're always collecting photos of species that didn't make this list — we want to showcase many more. Now that COVID restrictions have eased, please keep diving and posting your sea slug photos from anywhere in the world.