Sea lamprey is a parasitic fish that lack scales and gill covers. Similar to sharks, their skeletal structure is made of cartilage. They are native to the northern and western Atlantic Ocean along the shores of Europe and North America. This creature have a large mouth, filled with circular rows of teeth.
They latches onto its victims with teeth and gnaws through flesh and sucking the blood from its prey. Just like other fish, sea lamprey breathes using the gills. It has seven pairs of tiny gill openings located behind their mouths and eyes. Sea lampreys are able to live in both marine and freshwater. They spends a few years in the fresh water. After that time, it migrates to sea, where it stays usually around 2 years. During that time, sea lamprey will become mature and it will return back to fresh water for spawning.