Here are some pictures of the real thing. Leeches occur in a variety of colors, the reddish-brown shown, tan, olive and black. A full-grown, swimming leech with its body stretched out to near full-length can be as much as 3 1/2 inches or more long. They swim with an up-and-down, undulating motion (sinusoidal) which is very difficult to imitate involving a lot of movement but making little actual headway. My beadhead, rabbit-strip string leech has worked quite well for me.