Quote Originally Posted by Espritduo View Post
Eurhinosaur - Diadem skyfishing (Hard?)
Yes. You can catch at the Swirling Cloudtop during HM.

There doesn't seem to be a particular weather that it likes and you can catch with red balloon or crane fly. However, it's extraordinarily slippery; very rare nibble and likely to get away. This fish is used in no recipe, no quest, uncollectable, and stands to be another Barreleye--a difficult fish that desynths into nothing.