We first started intentionally fishing for carp in the early 00s, when a sustained drought regularly made our rivers too warm for trout to be happy in the late summer, but the hot water seemed to make these funny looking fish super spunky. What we found after some further research was that carp are abundant in certain waters of our state, they are fun and challenging to catch on a flyrod (arguably much more challenging than trout!), and they get really big; 5 to 15 pounds on average and up to 30+.
The best part of fishing for carp is that it's the closest we can get to saltwater flats fishing here in Montana. We sight fish for them, both wading and from boats, and often find them tailing just like a bonefish as they root on the bottom for crayfish and other tasty morsels. It takes a good presentation to fool a big carp, and it's a fun game to try if you haven't before. We also catch them on dryflies regularly, usually mayflies and grasshoppers, but occasionally on a cottonwood seed or mulberry.
Now don't get us wrong here, carp aren't going to replace trout as the Montana state fish or anything, but we think if you're into trying new things and enjoy the sight and stalk game that you should give this a try on your next Montana trip. It's a great way to tune up for your next saltwater flats excursion, that's for sure. It's what the locals are getting into, what many guides do with their days off, and has spawned at least one local tournament already.