Black-margined Nudibranch
Doriprismatica atromarginata
Pikachu nudibranch
Thecacera pacifica
About
This small sea slug is easy to overlook until you get close, then its bold colours and odd shape earn it a nickname shared with a cartoon character. It reaches about 3.5 cm and stands out sharply against plain reef rubble.
Also known as: orange sea slug, pacific thecacera, pikachu longhorn dorid, pikachu sea slug, thecacera pacifica, thecacera pacifica (bergh, 1884)
- Length
- 3.5 cm
- Depth
- up to 30 m
How to tell it apart
Many small reef nudibranchs share an orange body, so look instead at the head: the black-and-blue tipped horns sitting like a pair of ears are unique to this species.
Appearance
The body is see-through orange with a pair of tall, black-tipped horns (rhinophores, used to sense chemicals in the water) and feathery gills, also black-tipped, near the tail. The horn sheaths are edged in black with a patch of blue partway up, and the same blue shows at the tail tip and on the finger-like papillae beside the gills, each patch boxed off from the orange body by a black band.
Did you know?
Its nickname, the Pikachu nudibranch, comes from its likeness to the Pokemon character Pikachu, thanks to those two blue-based, black-tipped horns.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
