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.
Sedges and Reeds are superficially similar, but actually quite different. But unless you are a biologist - who cares? ( Reeds are grasses, sedges are sedges. )
Sedges
Sedges tolerate a wide range of salinity, from freshwater to seawater, although they seem to grow best in brackish water. So, like above, if you are exploring a bay or inlet, that stuff all around you is most likely sedge.