The marine animal in the picture may be described using a wide variety
of adjectives: beautiful, strange, cute, and fantastic. It could also be
called a science fiction monster, a Photoshop trick, a Mythical
Pokémon, or some sort of avatar… you name it!
It’s a nudibranch commonly known as “blue dragon” or “sea swallow”. It’s
a soft-bodied pelagic mollusk, a relative of snails and slugs. Its
scientific name is
Glaucus atlanticus. Blue dragons are small
(about 4-5 cm), pelagic, they drift upside down on the surface of the
ocean, they are hermaphrodites, and perhaps most importantly,
they are highly poisonous.
Blue dragons feed on other pelagic sea creatures such as the venomous
Physalia physalis,
also known as the "Portuguese Man-Of-War". They eat the stinging,
venom-filled tentacles of Physalia and concentrate the venom in the tip
of the dark-blue finger-like branches at the end of its six appendages.
This protects them from other marine predators.
