Male Mandarin Fish Synchiropus splendidus, Banda Neira Island, Indonesia - stock photo

Mandarin fishes inhabit shallow protected lagoons and inshore reefs. They occur in the Western Pacific from Ryukyu Islands to Australia, usually in small groups spread over small area in a depth range from 1-18m, max. length 7cm. Mandarinfish do not have scales, but a mucus layer for protection. It is not only a stinky slime they produce, but they also secrete a toxin to protect them against predators. Their dramatic colouration, known as aposematism, is a warning: unpalatability and toxicity - both prey and predator get to live longer. The couples perform an extraordinary courtship dance at dusk. Females gather at the reef, judging if a male is worthy. A male who has successfully courted a lady attaches to her at the pelvic fin. Then the pair swim up from the reef towards the waters surface, releasing a cloud of sperm and around 200 eggs smaller than 1mm. This specimen is a male: The presence of an elongated spine at the front of the first dorsal fin of males is distinctive. Females will not have this spike and will have a rounded first dorsal fin instead. In this case, there was a female too, but she didn't make it into the photo.Banda Neira Island, Indonesia, 4°30'40.842 S 129°53'19.71 E at 1.5m depth