Pliny

The Pliny are a type of Siren, a creature that resembles a humanoid on its upper torso and a fish on the lower half. They are shy creatures that lure sailors into drowning themselves so the Pliny can feast upon them.
They have the unique ability to shift the tones of their body to camouflage themselves within their coral territory better, typically coming in the form of bright colours. They also use these bright colours to lure fish in closer in order to make hunting them easier. They unlike some Sirens don't have an alluring song, but in place of this, they evolved to give their song the ability to put those that hear to sleep.
They can live up to half a century, but most die young, they are fertile since birth and only lay their eggs in the carcasses of sailors they have drowned. Their eggs are treated as a delicacy by nobles, without them knowing the true nature of the eggs being in the carcasses of men.