Swimming! Careful from Lampreys

Love swimming?  Be alert from these…
Most of us love swimming. But there is something known as Lampreys which everyone should be carefully off.
They have a round and sucker-like mouths that are filled with rows of teeth.

As grown-ups, they parasitize other fishes with their mouths and scraped their skin away.
They also release the anticoagulants which helps the blood to flow without problems from their hosts, most of whom die from extreme blood loss.