Mandarin Fish (Synchiropus splendidus) are reef dwellers, often found in sheltered lagoons and inshore reefs of the Pacific Ocean, ranging from the Ryukyu Islands of Japan to Australia. Despite their brightly coloured body, they are not easily seen due to their bottom-feeding habit (they feed on small crustaceans and invertebrates) and their small size – typically reaching only 6cm long.
There’s no denying that the Mandarin Fish is one of the most beautiful fish in the ocean. But there’s much more going on behind its pretty face.
Not a Goby but a Dragonet
Although commonly called Mandarin Goby, they are in fact not a Goby, but rather belong to the family known as Dragonets. Males tend to be larger than females and have a large pointed dorsal fin that is only occasionally displayed.
They use their large pelvic fins (not pectoral fins) for ‘walking’. Their real pectoral fins are located almost at the center and are nearly transparent, with a tinge of bright blue.
Produces its own blue pigment
The majority of blue-hued creatures tend to resort to elaborate optical illusions to brighten up their body. The microscopic layers of colourless crystals in their skin are layered in such a way that they reflect blue light back at the onlooker.
But the Mandarin Fish is the real deal as it does not rely on optical illusion. In fact, it is one of just two species in the world that produces its own blue colouring called ‘cyanophores’ – blue pigmented, light-reflecting cells that give it its vibrant colours.
Scale-less, smelly and toxic
This petite beauty’s notorious odour is not incidental. Without scales, it lacks the most basic protective measures in the marine world. To make up for it, it produces two types of secretions through its colourful epidermis – a thick mucus to shield it from parasites and the elements, and a smelly, toxic mucus to deter predators.
Beware the tiny spines
This fish is covered in tiny spines that inject toxic mucus into anyone who tries to catch it. The venom isn’t that strong, and feels pretty much like getting poked with a toothpick, leaving a red spot that dissipates after a few minutes.
In a bid to impress and attract potential mates, these fish engage in enchanting courtship dances to show off their beautiful colours, as seen in this clip by Australian Geographic:
According to National Geographic researchers, their spawning ritual is equally elaborate. A female joins the male, resting on his pelvic fin, and the pair rises slowly about one metre above the coral reef. At the peak of their rise, a cloud of eggs and sperm is released.
The gorgeous Mandarin Fish can be found at several habitats in the aquarium, but is best viewed at the Focus Lens tank located just further down the touchpool.
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