Xixi zhi yu

Xixi zhi yu is a mythical fish from China. It lives in the Raucous River, near the Trickling Brilliance Mountain. Stories of this fish mention that it has bird wings, it is also says that they who eat Xixi zhi yu will be cured from jaundice.

Explanation
The flying fish uses it's fins to glide, the flying fish may be the explanation for this cryptid. And the flyings fishes oil is used to heal sicknesses.