Deep Sea Unagis are derivatives of the Unagis that exist in Inazuma. These creatures are native to Enkanomiya and provide a supply of Unagi Meat for various dishes. These shy eels can also be caught with the Omni-Ubiquity Net to later thrive in your Serenitea Pot.
Deep Sea Unagi Locations
As Deep Sea Unagis can only be found in Enkanomiya, you need to get far ahead in your gameplay to unlock the region. But even in the ancient underwater world, Deep Sea Unagis are scarce and are extremely hard to find, as they camouflage with the environment. So if you're looking to farm Unagi Meat, you're better off farming from the Inazuma eels instead.
You'll find a small cluster of Deep Sea Unagi in bodies of water in the areas circled above. If you get too close, they'll get startled and retreat. If you have Sayu, her Yoohoo Art: Silencer's Secret passive allows her to approach Unagi without startling them. However, picking one up will still cause the others to retreat.
With that said, if you're looking to score some Deep Sea Unagis for your Wildlife Archive, make sure to catch them from a safe distance. If you fail once, they will retreat and you need to wait for them to come out of hiding to try again.
Check out our guide on How to complete the Collection of Dragons and Snakes World Quest in Enkanomiya in Genshin Impact to help you explore the region.