"A surreal form of manta ray; an highly rare and unknown catch..."
𝄖 Bestiary Entry.
Overview
The Aetherfin is an Divine Secret fish that can be caught in Roslit Bay. Due to its high rarity, it makes for a highly challenging catch, moving erratically across the fishing bar. When reeling it in, -95% Progress Speed is inflicted, as with all other Divine Secret fish.
When hooked, a 
will pop above the player's head, and a unique shimmering sound is played - as with all Divine Secret fish.
Obtainment
Aetherfin has a fixed 1/10000 (0.01%) chance be caught with any rod in any fishing spots in Roslit Bay. The chance of catching cannot be affected in any way.
Catch Quips
- A DIVINE SECRET!!!
Trivia
- Aetherfin has the highest chance to be caught among all Divine Secrets (1/10000 chance), same as Cataclysm Carp.