Mandarin fish have got to be one of the most colourful and truly ornate looking fish that we see in the Indo-Pacific. During the day time, whilst we do have occasional sightings, these little critters lay low and hide within the branches of staghorn corals. During sunset however, they leave the reef and perform one of nature’s most magnificent and flamboyant of mating rituals. It’s possible to see Mandarin fish at almost all of our incredible diving locations in Indonesia. Here are some Mandarin fish facts which you may not know, followed by our hotspots for sightings.

Mandarin fish hide in the staghorn corals during daylight hours

Fun Facts about Mandarin Fish:

• Mandarin fish (Pterosynchiropus splendidus) are also known by several other common names, including the Mandarin Dragonet, Mandarin Goby, Green Mandarin fish, Striped Mandarin fish and the Psychedelic fish.
• These little beauties are a small species only reaching about 3 inches in length.
• This species is best known for its ritual reproduction mating “dance” which only occurs during sunset hours. Females will group together at the reef and seek a male mate. The males then begin to court the females, the bigger and stronger males are more likely to be chosen. Males also can reproduce with multiple females in a night. The male and female pair attach at the pelvic fin and swim to the top of the reef where they release the eggs and sperm in a cloud (about 200 eggs). Once the egg and sperm clouds have been released the pair part ways and the courtship ends. The fertilized eggs take only 18-24 hours to hatch into larvae, then after two weeks of drifting, they settle into the reef.
• Mandarin fish they are very picky eaters. They eat mainly small worms, protozoans, and small crustaceans. The majority of our mandarin fish dive sites have areas of sand and patches of staghorn (branching corals). These sites are ideal as they provide protective corals and food for the fish.
• Scorpionfish are one of their most known predators.
• One of the biggest threats to mandarin fish comes from mankind and the tropical fish tank industry in which they are highly prized. Individual fish can sell for up to USD $150 – it has also recently been proven that, like many fish, they live up to 4 times longer in the wild than they do in captivity.

Mandarin fish are a small species measuring just around 3 inches in length

• Did you know that these fish do not have scales? Instead, they secrete mucus from their skin, which helps repel predators and keep them clean from parasites. Also, their bright coloration is not for attracting a mate, instead, it is to mislead predators into believing that they may be toxic to consume.
• Bold Colours but not bold characters: Mandarin fish are actually very skittish and shy, so they prefer to avoid other fish. This makes our mandarin dive site in Lembeh quite unique as they are often spotted living quite harmoniously in the staghorn corals with pajama cardinalfish and the endemic Banggai cardinalfish.

Look closely here and you can see the egg and sperm clouds being released from this mating pair

Here are some of our favorite hotspots for sightings when you are diving in Indonesia:

Mandarin Fish Lembeh

The best dive site is at Police Pier (aka Bianca) which is directly across the Lembeh Strait from Two Fish Divers Lembeh Resort and just 5 minutes by boat. We use this site as it is very reliable and we often see the fish mating.

The dive boat leaves at 16:30 and the dive is 60 minutes, with most of the time being spent in front of a large patch of staghorn coral waiting for the fish to come out and mate. There are also sightings of pipefish, octopus and plenty of nudibranch to keep you entertained while you wait for the mating ritual.

If Police Pier is busy there are also a couple of other dive sites where we dive, but did you know that at Two Fish Lembeh we also have a few mandarin fish on our house reef so you can go also searching for them any evening in your free time!

Male and females join by the pelvic fins prior to mating

Mandarin Fish Bunaken

At Two Fish Divers on Bunaken Island we see Mandarin fish at our Subsea dive site. It is a shallow dive in a lagoon where we often stay at 6m for 45-60 minutes. At the right time of the month, usually around the new moon, we see 10-15 mandarin fish mating or fighting and this usually happens around dusk so we depart at 16:30 and dive between 17:00 and 18:00. If you haven’t seen Mandarin fish before, or love this critter, it is a great opportunity to spend a whole hour with a “bucket list” species.

Mandarin Fish Gili Air

Mandarin Fish in Gili Air are found in the harbour. The Gili Air harbour is located on the southern tip of the island. The dive site is accessible from the shore without a boat, it is just a short five minute walk from the front door of Two Fish Divers Gili Air dive centre to where we begin the dive. The site is perfect for night dive with all sorts of crazy creatures.

In order to see mandarin fish we enter near the jetty at dusk and surface from our night dive just in front of our dive centre. The mandarin fish can be found in staghorn gardens just west of the jetty. The dive site is accommodating to all levels with a depth of 5m to 18m. The staghorn garden sits roughly at 13m.

The Gili Air Harbour is actually an excellent place for all sorts of unique creatures. The best place to explore is in and around the jetty and shallow slope for some really interesting creatures like frogfish, bobtail squid, seahorse, and robust ghost pipefish.

Mandarin fish mating is one of the highlights of diving in Indonesia

Mandarin Fish South Lombok (Secret Gili’s)

At Two Fish Divers South Lombok we have 3 or 4 locations where we can reliably and usually see mandarin fish throughout the day time (not mating though). We are looking forward to exploring these sites at dusk to capture the mating behaviour so if you’re interested in spotting this unique underwater action while you are with us just let us know!

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