Vampire fish really live! Sounds like the start of yet another really good b-movie, no?! Read on:
Currently there are about 38 known extant species of lampreys. Parasitic species are the best known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys are parasitic.
The lampreys are a very ancient lineage of vertebrates…
Adults superficially resemble eels in that they have scaleless, elongated bodies, and can range from 13 to 100 cm (5 to 40 inches) in length. Lacking paired fins, adult lampreys have large eyes, one nostril on the top of the head, and seven gill pores on each side of the head.
Studies have shown that lampreys are amongst the most energy-efficient swimmers. Their swimming movements generate low-pressure zones around their body, which pull rather than push their bodies through the water.
Parasitic lampreys feed on prey as adults by attaching their mouthparts to the target animal’s body, then using their teeth to cut through surface tissues until they reach blood and body fluid. Although attacks on humans do occur, they will generally not attack humans unless starved.
Well there’s a bit of encouragement there at the end, don’t you think? Nothing to worry about.
Read more about this blood thirsty critter on Wikipedia!