Freshwater leech

The Freshwater Leech, also known as "North American Leech" or the "American Medicinal Leech," is a worm that grows over two inches long. It lives in lakes, marshes, and slow-moving streams.
This leech is brownish-green with black and red spots, and it has a round, sucker-shaped mouth. They also have five pairs of eyes.
It is a parasite that feeds on the blood of fish, frogs, turtles, and mammals.
Freshwater Leeches spend the day under rocks or leaves on the lake or stream bottom. They detect their prey by the vibrations it makes in the water. The leech, which is an excellent swimmer, then comes out of its hiding place and attaches to the host animal. It can attach with its mouth or another sucker on its tail.
The mouth sucker has sharp teeth, which the leech uses to cut into the skin of the host animal. It releases an enzyme, which acts as an anesthesia and an anti-coagulant. The Freshwater Leech drinks blood until it is about five times its normal weight. Then it releases its grip and finds a new hiding place. The enzyme will cause the host to keep bleeding, even after the leech is gone, until it wears off.
Freshwater Leeches do not need to eat often. They can even go a year or two without a meal.
Leeches, just like their earthworm cousins, are hermaphrodites. This means that after they mate, both leeches can lay eggs. The leeches lay eggs inside small coccoons in the muddy bottom. Young leeches hatch from the coccoons when they are ready.