Mandarin Fish | Critters of the Lembeh Strait

Mandarin fish (Synchiropus splendidus) or the mandarin dragonet, is a small, brightly colored member of the dragonet family. They are one of the most colorful species that we see and are just one of the many highlights of diving in the Lembeh Strait. They display exquisitely ornate patterns of spots and stripes on both the males and females of the species. The name ‚Mandarin fish‘ actually comes from the colors of the ornate gowns worn by Chinese emperors.

When to see Mandarin Fish

In Lembeh it’s possible to see mandarin fish during your daytime dives, at sites such as Bianca (see below), where they weave in and out of the staghorn corals. However, the best time to see mandarin fish is during one of our mandarin dives which depart from the resort just before sunset to watch their unique mating behavior.

Mandarin fish pair prior to swimming up off the reef to mate

A courting Mandarin fish pair prior to swimming up off the reef to mate

Mandarin Fish Mating

Mandarin fish mate just before sunset and they put on an incredible show.

At sunset, the females will wait on the reef for the males to approach – which is when they begin to engage in courtship behavior. The females will choose a male, approach it and then attach themselves by resting on the male’s pelvic fin. Mating takes place in a belly against belly position – once they are in position, the male and the female will rise 1 meter above the reef together. When they reach the apex of their ascent they will spontaneously release sperm and eggs at the same time. Once the release has taken place, both the male and female will dive back down to the reef.

The eggs and sperm are then at the mercy of the currents. Fertilized eggs will hatch into larvae after just 18-24 hours. Larvae continue to drift for up to 2 weeks before settling down on the reef.

Mandarin Fish Defense Mechanisms

The bright colors of the mandarin fish are part of their defense mechanism and are meant to warn away predators. Although beautiful to look at, their small bodies are also covered in tiny spines to inject a toxic mucus (which covers their bodies) into any predators that attempt an attack.

A male and female Mandarin Fish in Lembeh Strait, North Sulawesi Indonesia

Diet

Mandarin fish live in colonies and inhabit small patches of reef – often up to only 10 square meters. They feed continuously throughout the day on small prey which has become trapped on branching corals. Their diet consists of small fish, plankton,  worms, small gastropods, fish eggs, and amphipods.

Threats to Mandarin Fish

One of the main threats to mandarin fish is the aquarium trade. Due to the bright colors of mandarin fish they are highly sort after by aquarium owners, collectors, and those in the aquarium fish trade.

Where to see Mandarin Fish in the Lembeh Strait

The dive site ‚Bianca‘, takes its name from the large phinisi boat, named Bianca, which is permanently moored at the site. This is a great site for seeing mandarin fish during the day, as well as several species of frogfish, and pajama cardinal fish.

For our sunset mandarin fish dives we visit a small patch of coral reef which is known as a mating ground and is just a few minutes from the front of Lembeh Resort. Our mandarin fish dives take place on certain evenings of the week, so if you would like to join a mandarin dive, let our dive center know.

Mandarin fish mating and eggs in Lembeh Strait

An incredible shot of Mandarin fish mating, and eggs in Lembeh

Mandarin Fish and Underwater Photography

For Underwater photographers who wish to capture shots of these colorful critters, patience is definitely a virtue!

The shots that most people want to capture are like the ones in this Blog, where the fish are together, above the reef. The best approach is to settle down close to the bottom and wait for the action to happen. Stay as still as possible so as not to disturb the mating.

Because of the combination of fading sunlight and because you will be shooting upward, you will need to be using a strobe or video light to capture the colors of the fish and the details. If you do not have suitable lighting with you, we have complete rigs and strobes available for rent from our photo center.

If you are not familiar with shooting at sunset, or would like personalized advice for shooting mandarin fish with your particular camera set up, call in to our Photo Center and talk to our Photo Center Assistants or Photo Pro. Our Photo Pro is also available for photography courses if you would like to take your shooting to the next level.

Luxury dive resort at Lembeh Resort

Premium Luxury Cottages at Lembeh Resort

Staying and Diving with Lembeh Resort

Lembeh Resort is situated in a secluded cove on Lembeh Island. We pride ourselves on our quality accommodation, service, and dining. Our dive guides are all trained in both marine biology and underwater photography and we have in-house Marine Biologists and a full time Photo Pro. Our Photo Center is the only Backscatter Authorized Photo Center in Indonesia.

If you would like to come and join us here at Lembeh Resort we would be delighted to welcome you, contact us today at: [email protected]