American Medicinal Leech
So here we are, back in Michigan. On May 17, 2013 we decided to have another look at the contents of the little pond back in the woods. So, we were poking around on the shore, and Sandy spotted an odd orange object in the weeds. Which we promptly netted, and found to be – A Leech! A big one!
It was only orange on the underbelly side, with the back being more a dark brown with small spots.
This looks to be an American Medicinal Leech, Macrobdella decora. These are big leeches that have sometimes been used for bloodletting purposes, although the European Medicinal Leech was more commonly used.
The little pond was crawling with them. Later in the summer, Sandy and the girls hauled our canoe down to the pond to go poking about, and ended up netting about a dozen of them as they swam by in their undulating way. Sandy later used them for fishing bait 
A big advantage of leeches as fishing bait is that they keep really well. A leech might go for a year or more between meals, so if you keep them in a jar of water in your refrigerator you’ll always have bait available. They also stay on the hook very well (you can hook them through the sucker, which is pretty tough and gristly), and being aquatic they won’t get “soggy” and listless the way an earthworm will. And fish really do love them.
 We also tried setting out various types of “leech trap” as discussed the last time I had pictures of a leech. None of the traps worked for us, though. So for our particular pond, and our particular leeches, netting is probably the way to go.
“So, as fast as I could, I went after my net. And I said, “With my net I can get them I bet. I bet, with my net, I can get those Things yet!” – Dr. Seuss