One of the more risqué dives offered through Evolution is to find the famous mandarin fish. Especially sought after by underwater photographers, this is a ‘risqué’ dive because the goal is to attain a ring-side seat to witness their mating ritual.
Mandarin fish mate almost daily; this would suggest that looks count for a lot in this game as they are known for being extremely smelly! Unusually, this fish does not have any scales and is instead covered in a slimy, stinky mucus. Fortunately, their beautiful colouration and elaborate mating ritual seem to tip the balance back in their favour, and we can regularly observe these shy and elusive fish going through their sunset rituals.
As with nudibranchs and lionfish, the bright colours and horrible smell are another example of aposemitism; overtly warning predators that they are not a suitable meal. Sometimes referred to as ‘psychedelic fish’ their bright colours and vivid patterns set the mandarin fish apart. It is these colours, reminiscent of an Imperial Chinese mandarin, that its common name references. This striking display is even more special as they are one of only two known species that produce their own blue pigment.
The key to this dive is patience; it’s a waiting game as you catch glimpses of colour slip through the coral branches. If you’re lucky your wait will be rewarded with one of the most spectacular underwater sights. Once a female accepts a male’s advance the two rise up above the reef together in a quivering, twirling embrace. It is this mating ‘dance’ that has brought them fame (and a loss of privacy), and at the culmination a cloud of up to 200 eggs is released for fertilization.