They can be left in a container of water for a long time without food. Walleyes love leeches almost all year round and they are classified as a universal bait for walleyes. Leeches inhabit lakes, ponds, marshes and slow moving streams, throughout most of North America. All leeches have sucking disks at both ends. The mouth is located in the smaller disk at the head end.
Leeches use the larger disk on the tail only for clinging to objects.
Most leeches eat dead animals. Some species such as the horse leech digest the skin of live animals and feed on the tissue. A few kinds, such as the medicine leech, are called bloodsuckers. They have jaws which actually cut through skin to reach blood vessels and tissue. Not all kinds of leeches attract fish.