-About 1 millimeter to 5 centimeters in length

-They have flat body when swimming

-They always consist of 34 segments

-They have suckers on both ends of the body

-Found in warm protected lakes, ponds, streams, and marshes

-They often hide under rocks and vegetation

-Silty substrates are a hazard to leeches because they can not attach well

-They also have a dark color such as black, dark green, or brown