Along with the Orca Migration Event, the other prominent notable inclusion in the post-Atlantis update was the addition of a brand new landmark called Oil Rig/Refinery on the map. This new territory has also brought back the fan-favorite Dr. Glimmerfin NPC to the game. So, here is a detailed explanation of the location of the Oil Rig and all the hype surrounding it.
The newly added Oil Righ POI is located at the GPS coordinate (X:-1793, 130, -480). This is located right somewhere between the Forsaken Shore POI and the Grand Reef. Travel to this destination to find a big Oil Ring on the ocean floor.
After reaching the Oil Rig, you can climb to the first floor, where you will find multiple other NPCs along with Dr. Glimmerfin at the center. Though Glimmerfin does not reveal much, interacting with other NPCs at the location shows that the Oil Rig is pretty much under construction, and Glimmerfin requires some sort of Fin at the top of this building. These dialogues are connections to future quests or lore of the Fisch universe that are pretty much under wraps at the current moment.
I personally predict that, like previous Glimmerfin's Quest, you will be required to catch certain items/fishes in the coming weeks that might be used to complete the building, which in turn will serve as a new landmark with a new set of bestiary.
At the moment, you cannot catch any fish at Oil Rig POI, which means there is no bestiary to complete. However, the entire community and I predict that there will be some sort of bestiary available at the location once you have solved the Glimmerfin's Quest, which remains a mystery.
For more on Fisch, Check out Roblox Fisch Private Server Links or All Fish Locations and Best Bait in Fisch Roblox