Night Diving to See Mandarin Fish Mating In Lembeh, Indonesia
Mandarin fish, commonly known as Dragonet fish, are very colorful, with beautiful patterns on its body.
It is the most popular and requested fish in salt water aquariums, even though it is hard to keep in captivity.
This is because in captivity, a Mandarin fish will not eat factory made fish food.
It requires large amounts of live, tiny shrimp, copepods, and worms.
Because it is nearly impossible to recreate the conditions of its natural habitat in salt water aquariums, it often dies from malnourishment.
Mandarin Dragonet fish live in warm tropical waters.
They dwell at the bottom of the sea, among broken corals, no deeper than 18 meters (60 feet).
During the day, they tend to sleep and hide in the coral, while at night they swim out into the ocean.
In Lembeh, the Mandarin fish are found at a shallow site aptly named the “Mandarin Fish Dive Site.”
It is a late afternoon dive that stretches into the night.
We left the resort at 5PM, when the daylight was already growing dim.
I was equipped with a small flashlight and was told not to use it directly on the Dragonet fish, as the bright white light would chase them back into their hiding places inside the corals.
We arrived at the site by 5:15 PM, and were instructed to dive down to the bottom of the sea and rest on our knees in front of the coral.
The location was full of long spiny sea urchins, which give a painful sting if you were to touch them.
After crouching on my knees, I was instructed not to move and to wait until darkness, when the Mandarin fish comes out to mate.
I leaned on my knees in front of the broken coral reefs in the shallow water, one eye observing the spiny sea urchins that were changing positions, and the other eye looking for the Mandarin fish to emerge.
Suddenly they emerged, one by one.
Mandarin fish are very distinctive because of their shape and intense coloration.
They have a broad, depressed head and many primary colors, like blue, orange, red, and yellow, in wavy patterned lines.
The intensely bright colors and the wavy patterns are part of their protection from predators.
The males are noticeably larger than the females.
Mandarin fish do not have scales; they instead have a thick mucous coating that omits an unpleasant smell.
The smell is not noticeable by divers, since our noses are enclosed inside our masks, but it is another deterrent for predators.
Mandarin fish mate all year round, and external fertilization occurs when a male and female are in close contact and swimming upward.
It was not easy to photograph them mating, as they move fairly fast and stay in contact only for a few seconds at a time.
Females produce about 200 eggs, which have a short incubation time.
The newborns develop quickly.
The eggs are colorless, and at first they are clumped together; then slowly they break up into smaller units.
The eyes and mouth are formed and become pigmented only 36 hours after fertilization.
In 12 to 14 days, the juveniles have fully formed bodies.
At 18 to 21 days, the body darkens to brighter colors, and the dorsal spines can be seen.
By the second month, their adult colors and patterns are developed.
After kneeling at the bottom of the sea observing Mandarin fish mate, I got a little chilly.
I asked my dive master to move around a bit to get warmer.
We made our way in the dark sea, pointing with our torches to illuminate the way.
There is something serene and unearthly quiet about diving at night.
I felt like a tiny sperm swimming inside a dark womb.
The rest of the photos here are from three other dives that I did in Lembeh.
I have been posting in the past week a lot of photos that I have taken with my tiny Olympus Tough camera during my dives.
I was lucky and fortunate to have a couple of photographers on my dives who also stayed at our resort.
While on the boat between dives and over our communal meals, I got lots of tips about how to use my underwater camera effectively.
Because I do not have an underwater housing for my camera, I had to limit my dives to 60 feet in depth.
If I dive deeper than that, my camera gives a depth warning signal.
Anyway… I posted many photos from my dives, and will continue to do so until we leave Indonesia and get to Japan.
I have been very taken by the beauty of the sea, and also this has been my first diving trip in three years.
Another factor is that beside diving, eating, reading and resting, there is not much to do at a dive resort…
From Sulawesi, I am sending you love and colorful photos of Dragonet Mandarin fish….