Full disclosure: the only trout I ever caught I shot with a .22. I'm strictly of the still water and bobber school of fishing, with worms or cheese balls for bait. I'm a few miles from some blue ribbon trout streams but never learned to fish running water. Further truth, I'm not that crazy about trout.
What I really like are bullheads (horned pout, mud cat). I've been told there is excellent fishing for them in Ninepipe Reservoir. The rub is that requires both a Montana fishing license and a Flathead Reservation permit.
I live on the river and probably could fish the sloughs and backwaters but Fish & Wildlife recommends not eating the fish very regularly and to skip the pike entirely. The actual Superfund site is upstream but it trickles down.
The north end of Flathead Lake is not in the rez and is teeming with lake trout.
That was another great idea gone off the rails. Macks had been around since the early 20th century but were rare. Then kokanee salmon were introduced for sport fishing. Kokanee mainly eat zooplankton but some genius decided mysis shrimp would be a good food source. Seems the shrimp are a lot more efficient at eating zooplankton than the kokanees so the kokanees died out. The young lake trout, on the other hand, found the shrimp nutritious and delicious and the population exploded to the detriment of the other native species.
They did the same thing at Tahoe: