Blue dragon (Glaucus atlanticus)

Key facts

Scientific name

Glaucus atlanticus

Common name

Blue dragon

Category

Molluscs

Family

Glaucidae

Genus

Glaucus

Size

2–4 cm

Depth

0–1 m

IUCN status

Least concern (LC)

Danger level

Harmless

Habitats

open-water

Behaviours

pelagic, venomous

Ocean zones

Asian Pacific, Caribbean, East Atlantic, Eastern Pacific, Indian Ocean & Red Sea, Macaronesia, Mediterranean

Description

Glaucus atlanticus reaches 4 cm. Extraordinary small pelagic aeolid nudibranch (Glaucidae) floating at surface (0 to 1 m) of tropical and temperate oceans (Atlantic, Indo-Pacific). Brilliant silvery-blue body dorsally, white ventrally (counter-illumination camouflage), with cerata with silver-blue tips arranged in plumes. Lives attached under water film (flotation by gastric air bubble). Feeds exclusively on venomous pelagic cnidarians (Physalia physalis, Velella) whose most powerful cnidocytes it sequesters for its own defense. Painful sting. Legendary macro photo subject for its alien appearance and venomous pirate behavior.

Photo of Blue dragon

Frequently asked questions

How big is the Blue dragon?

Blue dragon (Glaucus atlanticus) reaches 2–4 cm in length.

At what depth can you find the Blue dragon?

Blue dragon is found between 0–1 m deep.

Is the Blue dragon dangerous to divers?

Danger level: Harmless.

What is the conservation status of the Blue dragon?

IUCN status: Least concern (LC).

Where can you find the Blue dragon?

Found in: Asian Pacific, Caribbean, East Atlantic, Eastern Pacific, Indian Ocean & Red Sea, Macaronesia, Mediterranean.

Similar species

• Aliger gigas - Queen conch
• Chromodoris magnifica - Magnificent chromodoris
• Phorcus turbinatus - Turbinate monodont
• Octopus vulgaris - Common octopus
• Hypselodoris picta - Painted hypselodoris
• Felimida purpurea - Purple doris

Sources

• Taxonomy: WoRMS (AphiaID 140022)
• Photos: iNaturalist (CC BY-NC)
• Distribution: GBIF (taxonKey 5190072)
• Conservation: IUCN Red List
• Encyclopedia: Wikipedia