Hello,
Crappie minnows- the smallest minnow sold at bait shops and are used for panfish.
Fatheads minnows- are a step up from crappie minnows and are used mainly for walleye but can be used for crappies, perch and bass.
Sucker minnows- they are normally sold in a few different sizes small, medium, large, and decoy. Small suckers are used for walleye, bass and smaller northerns. Medium suckers are mainly used for northerns and maybe muskies but can be used for walleyes and catfish. Large suckers are used for northerns, muskies, and flathead catfish. Decoy suckers are big normally 12+inches and are used by catfisherman for cutbait, cut them into chunks or filleted and cut into strips, but can be use live for muskies, and flathead catfish. They are also used by northern spear fisherman through the ice, there attached to a harness and lowered in the spear hole to attract northerns, that is how they got there name (decoy suckers)
Shinner minnows- come in a few different sizes small medium and large, they can be used for walleyes, northerns, and muskies. They are hard to fined dureing the summer but are readally avalible dureing ice fishing season.
I hope this help and good luck fishing.
Take care!
Kevin