The waters surrounding Phu Quoc Island are not only teeming with fish but they are also teeming with glow in the dark plankton (biaoluminescent algae).
When the sun has set and the moon is waning, a ethereal phosphorescence can be seen in the water along the shores of Phu Quoc caused by plankton which are only visible at night and emit a blueish glow when the water surrounding them has been disturbed, either by your hand or a gentle wave. One of the most amazing and natural experience you can have on the island is by swimming at night with the stars above you and the water glowing around you.