Note how the mouth of the Largemouth extends under the eye, while that of the Smallmouth stops short of it. A lot of fishermen seem to think everything they catch is a Largemouth.
There are many different types of minnows in North America, but the one you are most likely to encounter kayaking is the Golden Shiner, and there is a good reason for this: If you are out after dark and you have a light, they will jump at it and can end up in the boat.