Se tu

The se tu was a large, green species of fish whicch apparently enjoyed taunting potential fishermen. During Team Avatar's travels near Makapu Village, Sokka attempted to catch one and failed miserably.

Anatomy
The se tu was found in the rivers of the southern and western Earth Kingdom. It had two short whiskers positioned directly below the eyes, as well as a long dorsal fin running from the top of its head down the spine, and two greenish-yellow pectoral fins positioned below the large blue stripes that traversed the sides of its body.

Connection
Although there are no solid green catfish like the one seen in Avatar, catfish inhabit freshwater habitats throughout the world. The se tu is also similar to the salmon in their spawning ritual. These fish are very similar to the "fish-men" from The Legend of Zelda: The Wind Waker.

Behavior
These fish are known for their habit of repeatedly jumping high out of the water, often looking to spectators as if they were taunting them. The fish are said to have "thoughtful" eyes and human-like features. They are the favorite food of the platypus bear and have been known to grow to the size of full-grown man. Once a year, these fish swim hundreds of miles up river to spawn.