Mandarin Fish Mating: I’ve Witnessed What Happens!

mandarin fish looking for mate

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As a scuba diver, one of my favorite things about being underwater is seeing all the different animals in their natural habitat. So when I see these creatures interacting and I get to witness their behavior, that gets me pretty excited.

It is very common to see fishes eating swimming and protecting their territories. But mating? Those are pretty rare! Out of a hundred dives, I’ve probably seen one or two species getting it on underwater. So, witnessing fishes “doing it” is very uncommon. In fact, most of the time it is just by pure luck.

When I heard that there were Mandarin fishes in Moalboal and I could potentially witness their mating ritual, I knew I had to pay a visit to one of my favorite fishes in the ocean.

What is a mandarin fish?

Mandarinfish or Synchiropus splendidus.

The mandarinfish or Synchiropus splendidus belongs to the dragonet family. Its common name, “Mandarin” fish, is named after the colorful robes worn by the bureaucrats during the Chinese Imperial period.

Some people has also called this the psychedelic fish because of its blue, green, and orange wavy patterns on its body.

I first learned about mandarin fishes while browsing a reef fish identification book. When I saw its beautiful colors on the glossy pages, I knew I just had to put this attractive fish on my marine life must-see list.

Where do mandarin fish live?

The mandarinfish can be found in the Pacific region, from Hong Kong down to Australia.  To my delight, this included the Philippines! This meant I didn’t have to go far just to see one.

Red Mandarinfish spotted in Lembeh, Indonesia. Photo by Shawna Lietzke
Red Mandarinfish spotted in Lembeh, Indonesia. Photo by Shawna Lietzke.

The mandarinfish are tropical marine fish often found at depths of up to 18 meters. They thrive in water temperatures of 24 to 26ºC. These bottom-dwelling fishes are often found in coral reefs and shallow lagoons. The mandarinfish are shy creatures and like hiding under foliose and dead corals.

Back in 2013, while learning how to scuba dive in Coral Cay Conservation, I was told that there were mandarinfishes in Napantao, Southern Leyte. On one of our afternoon fun dives, I requested my dive buddy, Bram, to show me the mandarin fishes. We found 3 of them hiding in a patch of dead branching Acropora and immediately checked it off my bucket list!

How big are madarin fishes?

As usual, I had not paid attention to the reef book description on how tiny mandarinfishes were. I had difficulty spotting them right away because these colorful creatures are known to grow up to 3-4 inches only.

They are known to be shy and skittish too, making it even more challenging to observe them underwater. If you want to get a glimpse of one, better get ready to play hide and seek with these tiny dragonets.

When is the best time to see mandarin fishes?

Since it has been 6 years since I last saw mandarin fishes, I thought it would be cool to try to see them while we were diving in Moalboal. In the past, we spotted them during an afternoon dive, but the best time to actually look for them is around dusk.

At around 5:30 PM, we geared up and headed to the house reef dive site in Moalboal. The sun hadn’t set yet when we reached the patch of dead corals where they are often spotted. Hovering over the corals, I tried searching for them but could not find them.

Overhead, I noticed the sun had finally set and it was starting to get dark. Along with it, my mood slowly turned to disappointment. Did we arrive too late and totally missed the mandarin fishes?

Out of nowhere, I saw the familiar blue, green, and orange body of the mandarinfish peeking out from all the rubble. Yay, it’s here!

Then I saw another, and another, and another… They’re all here!

Mandarinfish in Moalboal, Cebu
The cute and tiny mandarinfish in Moalboal.

How to properly observe mandarin fish mate?

Turns out the less sun and less light there is, the more they are willing to come out. They sure don’t like being in the spotlight.

I was overly excited to see them. And to be honest, I was all over the place trying to get a peek of them in the rubble. I noticed our dive guide signaling for me to kneel on the broken, dead corals nearby. Apparently, I was spooking the mandarin fishes by hovering! Whoops!

Observing mandarin fish mating requires a lot of patience and stealth, which I seemed to lack. But once I settled down, more mandarin fishes started darting in and out of the branching dead corals.

If you plan to do some underwater photography, having strobes or a flash would come in hand. You will also need to keep your distance and zoom in. As usual, I came unprepared and barely got any decent shots of the experience. Before diving, I wish I read this guide on how to photograph mandarin fishes.

At this point in the experience, it had transitioned to a night dive and we had to use our dive lights. We tried our best to redirect any light that was coming from our torch to avoid scaring them off.

The mandarin fishes appeared to be chasing each other and playing among the dead corals. Since it was finally dark, they seem to be more comfortable out in the open.

I soon realized that we were already witnessing part of the mandarin fish mating ritual. And we were at the front row seats!

So let’s get to the good part already… Show us the mandarin fish mating!

How do mandarin fish mate?

Mandarinfishes like to court and woo their potential mates. The smaller, female mandarinfish gets to choose the bigger, male mandarinfish she wants to mate with. Once she has chosen she attaches herself to the male’s pelvic fin and the underwater mating ritual ensues!

While the mandarin fish are mating, the fish couple looked like they are dancing with their bellies and cheeks stuck to each other. It was kinda sweet and romantic really.

Then, with their fins fluttering, they slowly rise above the corals into the open water. When they reach their peak (wink, wink), they release their sperm and eggs at the same time, creating a cloud of future baby mandarinfishes.

Luckily, I managed to capture this magical moment. If you want to see the mandarin fish mating, check out my video below!

It was a quickie but I captured the mandarin fish mating!
Here’s a professionally taken underwater video of mandarin fish mating.

How are mandarinfish babies made?

Of course, making a baby mandarinfish isn’t as simple as that. Each female can only release her eggs once each night and can only release up to 200 eggs. Although the Mandarinfish can breed all year round, they are pelagic spawners.

So after the mandarin fish mating ritual, when external fertilization occurs, the eggs will hatch into larvae. Then, they will remain plankton for about two weeks.

This means that their babies will be carried out by the current and will be at the mercy of the dangerous ocean. During this time the developing mandarinfishes could be eaten by other creatures. They also could be exposed to unfavorable ocean conditions that could lead to their demise.

For the lucky ones that survive and find the appropriate habitat in the reef, they can live for 10-15 years!

What preys on the mandarinfish?

Another interesting fact about the mandarinfish is that unlike other fish that have scales, this critter is covered in a thick coating of slime. They secrete mucous that has an unpleasant smell and bitter taste which makes them less appetizing for other predatory fish. (Curious to know what the scientists did to find these out!)

Although the scorpion fish have been known to feed on the mandarins, most predatory fish avoid them. The intense coloration of the mandarinfish serves as a warning to their predators that they are actually toxic.

On the other hand, this same coloration has attracted the biggest predators of them all. Humans.

Mandarin fishes are high in demand in the aquarium trade. Once mandarin fish are caught and sold to private aquariums, the average life expectancy of the mandarinfish declines to 2-4 years.

Mandarinfish in an aquarium
Mandarinfish in an aquarium. I don’t know about you, but it looks sad!

If you want to see these beautiful creatures, I highly recommend that you see the mandarin fishes in their natural habitat. Put this in your bucket list now!

Moalboal is a very good place to do it and if you’re lucky, you’ might actually see the mandarin fish mating too. I guarantee, it will be Synchiropus splendidus!

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Have you seen these cute critters before? Have you seen the mandarin fish mating? Where did you dive to see them?
Leave a comment below!

The links above may be affiliate links. If you shop through them, I’ll earn a commission at no additional cost to you. For full information, please see my disclaimer here.

Ara Juan

Ara is the founder of DiverBliss.com and PhilippineDives.com. She is a PADI Rescue Diver with a goal to dive in all the best places around the Philippines.

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