Oarfish

The Oarfish is an fish that can be found in the ocean. It appears from December to May. It will appear all day. When selling it to Re-Tail, the player will earn 7,200 Bells.

Location
The Oarfish is found in the ocean.

The Museum
The Oarfish can be donated to the museum. Upon doing so, the following text is given by Blathers:

"Oarfish are deep-sea-dwelling fish with long, thin, silver bodies and one red fin lining their backs. They can reach lengths of over 10 yards, making them huge and striking fish. They usually swim by twisting their long, thin bodies, but they can also swim in more vertical positions. Their mouths are small compared to their bodies and they have no teeth, so they're large but not imposing."

Quote
Upon catching the fish, the player will say the following:

"I caught an oarfish! Good, I needed a paddle!"