With its vibrant, stained-glass coloration, divers may think it would be easy to spot mandarinfish on a reef. But don’t be fooled — these tiny jewel-toned fish are very shy and emerge only at dusk, so spotting them is a real treat.
What are mandarinfish?
Part of the dragonet family, mandarinfish are named for their vibrant colors, similar to an imperial Chinese officer (Mandarin). They are quite small, up to only 2.4 inches (6 cm) in size and feed mainly on small worms, crustaceans, and other small invertebrates. Interestingly, these are one of the few fish that do not have scales. Instead, a mucus-coated skin protects them from diseases and predators.
Where are they?
You can find mandarinfish in the Western Pacific Ocean from Malaysia to Australia. They usually live on shallow reefs or among coral rubble in protected waters. They seek out habitat with lots of hiding places.
Why are they so hard to spot?
Not only their small size makes it difficult for divers to spot mandarinfish, but also their habits: they are quite shy and are bottom dwellers, so they spend a lot of time dissimulated in the reefs. Their mating ritual is quite specific and usually happens around sunset. A few females will gather in a specific spot on the reef and the males will visit and court the females. Once the male is successful and has impressed a mate, the female will come and rest on his pelvic fin.
The pair will rise together, belly-to-belly, a few feet above the reef, where they will release sperm and a cloud of eggs before parting. The fertilized eggs will then drift in the current and take about 24 hours to hatch. This ritual is quite special to watch, so in places where mandarinfish commonly live there are often sunset dives specifically to see them.
How can you increase your chances of spotting one?
The Coral Triangle is the best place to spot a mandarinfish. Local dive shops will usually know good spots to find them, and as mentioned, dusk is the best time for a dive.