The fins of dying cod and some tropical fish show z-fighting

1. Place a cod on dry ground and watch it die an agonizing death (you monster!)
2. You'll notice that the fins of the cod show z-fighting (see screenshot)

This neither happens with other dying fish nor with fish swimming in water (including cod).

UPDATE 18w10a:
Some of the new tropical fish variants show this issue too, I don't know their specific names though.