Are you camping on the east or west side of the divide? If you're on the east side, check out some of the lakes on the Blackfeet Reservation. Duck can be fished from shore, as can Mitten, Twin and some others, although float tube opens up more possibilities. There are some huge trout in them - damselflies may be coming off now. Word of warning, it gets very windy. If you don't have a tube, I know that Lakestream used to rent them.

Regards,
ScottP