Synchiropus Splendidus Spawning

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Synchiropus Splendidus Spawning

Arguably among the most stunningly beautiful fish and a highly prized find by underwater photographers and divers alike, the Synchiropus splendidus (Mandarinfish) body is decorated with elaborated dots, swirls and waves of orange, bright blue, yellow and green. Widespread throughout the Phillipines and westward to Indonesia and Borneo, they’re usually found in very shallow water preferring the shelter of coral on reef crests and slopes. And we were very fortunate to have witnessed and photographed the Synchiropus splendidus spawning when diving at the south-eastern coast of Sabah.

On the fringing reef of Mabul Island, sandwiched between Borneo Divers and Seaventures Resort is Paradise, home to thriving numbers of mandarin fish. Colonies reside among the corals in just six metres, providing ultra convenient accessibility. The site is manageable even when surrounding currents are strong and can be shore dived from Mabul.

Synchiropus Splendidus Spawning

The male mandarinfish is larger and overall more robust; he has proportionately larger caudal and dorsal fins, but the most distinctive difference is the elongated dorsal spine being almost twice the size of the female.

Around sunset, groups of three to five females congregate in particular regions of the reef; males will go to these areas and display mating behaviour by raising their elongated dorsal fin. A male may visit several different groups in one evening.

Synchiropus Splendidus Spawning

During the mating process the female Mandarinfish gently rests on the males’ pectoral fin. Her belly is full with eggs about to be released.

In the mandarinfish world, size does matter! Females prefer to mate with the largest male as smaller males may require two or three attempts at a successful synchronised release of eggs and sperm. During the mating process the female gently rests on the males’ pectoral fin, simultaneously they rise together in the water column up to one metre above the reef. At the climax, in a split second the eggs and sperm are released and the fish disappear. The fertilised eggs are then left to the devices of the ocean currents. After 18-24 hours they hatch into one millimetre long larvae and remain planktonic for up to two weeks before settling onto the reef to begin their benthic life.

Synchiropus Splendidus Spawning

Mid spawning, the female’s underbelly is now much smaller. The eggs are released and can be seen around the tail fin.

As we fin away to end our dive we enjoy the myriad of marine life surrounding us. Among the vibrantly coloured corals illuminated by our torchlight, we spot a stumpy spined cuttlefish and a juvenile painted frogfish. The Synchiropus splendidus spawning had left us in awe. It was all over too quickly and once again we’re delighted and amazed at what this little piece of Paradise has produced for us.

Synchiropus Splendidus Spawning

Parental duties completed, fertilized eggs drift in the ocean currents.


About the Author:

Platinum PADI Course Director and Managing Director of Downbelow Marine and Wildlife Adventures. A PADI 5 Star IDC Dive Centre, Adventure Tours and Travel Company, Dive Shop and Adventure Lodge based in Kota Kinabalu, Sabah. Richard is a Professional Underwater Photographer and an active Marine and Conservation Enthusiast.