Pikachu Nudibranch
Thecacera pikachu
Thecacera pikachu is a small polycerid nudibranch formally described in 2026 from Tasi Tolu Bay near Dili, Timor-Leste, and named after the Pokémon character that divers had compared it to for years. Until then, the animal photographed across Southeast Asia as the "Pikachu nudibranch" was usually filed under Thecacera pacifica. Its body is pale orange and decorated with tidy black dots: two rows follow the edges of the back and join near the tail, more sit low on each flank just above the foot, and a pair of larger dots lies on the midline between the rhinophores and the gill. The tall, finely ridged rhinophores and their open sheaths are spotted as well, and two long, round-ended processes beside the five-branched gill reach about half the length of the body. Adults grow to roughly 4 cm. The Japanese T. pacifica, by contrast, is yellow to deep orange without the dotted pattern, and its appendages fade from black into sky blue. T. pikachu is recorded from the Philippines, Indonesia, Malaysia, China, Japan and Timor-Leste. Most sightings come from night dives, when it crawls over sand and coral rubble grazing on bryozoans and hydroids, so slow searches of rubble slopes after dark give the best chance of finding one.
Where to see Pikachu Nudibranch
Dive sites where Pikachu Nudibranch is recorded.
Thecacera pikachu is a small polycerid nudibranch formally described in 2026 from Tasi Tolu Bay near Dili, Timor-Leste, and named after the Pokémon character that divers had compared it to for years. Until then, the animal photographed across Southeast Asia as the "Pikachu nudibranch" was usually filed under Thecacera pacifica. Its body is pale orange and decorated with tidy black dots: two rows follow the edges of the back and join near the tail, more sit low on each flank just above the foot, and a pair of larger dots lies on the midline between the rhinophores and the gill. The tall, finely ridged rhinophores and their open sheaths are spotted as well, and two long, round-ended processes beside the five-branched gill reach about half the length of the body. Adults grow to roughly 4 cm. The Japanese T. pacifica, by contrast, is yellow to deep orange without the dotted pattern, and its appendages fade from black into sky blue. T. pikachu is recorded from the Philippines, Indonesia, Malaysia, China, Japan and Timor-Leste. Most sightings come from night dives, when it crawls over sand and coral rubble grazing on bryozoans and hydroids, so slow searches of rubble slopes after dark give the best chance of finding one.