Pacific lamprey

The Pacific lamprey (Entosphenus tridentatus) is an anadromous (reproduce up rivers) parasitic lamprey from the Pacific Coast of North America and Asia. It is a member of the Petromyzontidae family. The Pacific lamprey is also known as the three-tooth lamprey.

Description
Pacific lampreys grow to about  as adults. They move from the ocean up rivers to reproduce. and reproduce once before dying. They have thin, long bodies with two fins on its back starting far back on the body. The anal fins are simple and the lower lobe of the tail fin is larger than the upper lobe and both lobes are joined with the dorsal fin and the anal fin. Adults living in the sea are a bluish-black or greenish colour above and pale below, but those in fresh water are brown. This species is known for having three (or occasionally two) sharp teeth. The Pacific lamprey are often found at sea or often far offshore. At sea, depth: near surface to 1,508 m (4,946 ft) 

 References 

Category:Agnatha