Rarely seen Catching the "vampire" fish

A parasitic "vampire fish" rarely seen by humans, called the "sea lamprey," has been reported to be spotted in the Virginia River (Potomac).

The fish got its nickname (vampire) because of the shape of its mouth and pointed teeth, which it uses to grab its victim and suck out body fluids.

A video clip has been circulated on Instagram showing how to catch the vampire fish.

The Potomac River has been polluted for so long that the government has taken steps to clean it up, so the appearance of the sea lamprey is a sign that the pollution is subsiding, because this creature is sensitive to toxins.

The sea lamprey is an invasive species native to the Atlantic Ocean, but it invaded the Great Lakes in the 19th century through man-made canals and shipping docks.

The fish migrate from the Chesapeake Bay to the freshwater river every year to spawn, suggesting this is not the first sighting.

After sea lampreys reach maturity at 4 to 5 years of age, they leave freshwater rivers to live out their lives in the ocean, the Chesapeake Bay Program said.

Sea lampreys have been around for millions of years, but are threatened by habitat loss and chemical treatments that kill lamprey larvae. They have the appearance of a sea snake, with a body that ranges from 12 to 22 inches long, and brown and yellow skin covered in dark spots.

These fish can sting humans swimming in the water, and although the sting will not be fatal, it is painful and can cause wounds.