The Best Fish to Catch in Montana This Summer

Quick Take

• Catching certain Montana fish legally requires you to kill them on the spot. Releasing them back into the water is actually the violation. Mandatory-kill rules explained →
• One fish on this list has no statewide bag limit whatsoever, and summer happens to be the single best window to land one. No bag limit this summer →
• Knowing the right time window each day dramatically changes your odds for most of these species, though it is not the window most anglers assume. Optimal fishing times →
• One prized Montana native can be fully protected in one stretch of river and legally kept just a few miles downstream. Varying bag limits by location →

Home to the Rocky Mountains and Yellowstone National Park, Montana is also the perfect place to wet your line. The waters are full of game fish, and some of them peak during the warm summer months. If you want to make so many catches that your arms get tired, you’ll need to know what species to target. Continue reading to discover which fish are biting in Montana this summer.

Northern Pike

The Northern Pike (Esox lucius) is a popular summer sport fish easily recognized by its long, torpedo-shaped body, dark green skin with light spots, and mouth filled with razor-sharp teeth. While trophy specimens in Montana can exceed 40 inches and weigh 20 to 30 pounds, the average summer catch ranges from 16 to 30 inches in length and 2 to 4 pounds.

During the heat of mid-summer, these solitary ambush predators seek refuge from rising water temperatures, making early morning and late evening the most successful times to cast for them. At these times, they’ll be found in dense weed beds, near submerged structures, and in cooler drop-offs. The bag limit for Northern pike in Montana is 10 per day and in possession statewide.

Walleye

Walleye (Sander vitreus) fishing shifts to deeper, cooler waters as Montana’s lakes warm. These sleek fish feature a distinctive olive-to-golden-brown back, lighter sides, a white belly, and large eyes adapted for low-light hunting. In the summer, walleye typically average between 14 and 18 inches in length and weigh 1 to 3 pounds, though trophy fish can far exceed these averages.

The most successful times to catch walleye during the summer are on windy days and during the hours around dusk and dawn. In some regions, such as Western Montana, all walleye caught must be killed immediately and kept, with no catch-and-release allowed. Regulations may differ in other areas, so always check local rules.

Grass Carp

The grass carp (Ctenopharyngodon idella) is a massive, herbivorous fish in the minnow family, classified as an exotic, non-game fish in Montana. It is easily distinguished by its silver-to-olive-brown body with large, dark-edged scales, a broad head with small eyes, a short dorsal fin, and the absence of mouth whiskers (barbels) found on common carp. These powerful fish reach impressive average lengths of 2 to 4 feet and weigh between 15 and 40 pounds, though they can exceed 60 pounds under optimal conditions.

Summer is the best time to fish for grass carp because rising water temperatures maximize their metabolism, driving them to feed voraciously on aquatic plants near the surface in weed-choked flats, quiet backwaters, and reservoirs east of the Continental Divide. Because grass carp are a non-native species introduced for weed control, there are generally no statewide daily bag or possession limits, but anglers should check local regulations for any area-specific restrictions.

Smallmouth Bass

The smallmouth bass (Micropterus dolomieu)  is a feisty game fish with a bronze-green hue and dark, vertical bands. Averaging 12 to 16 inches in length and 1 to 3 pounds, smallmouth bass thrive in Montana’s warmer summer waters.

The most successful times to fish for smallmouth bass are early morning and late evening, around rocky points and drop-offs in rivers and lakes throughout the state. In some regions, all smallmouth bass caught must be killed immediately and turned in to Montana Fish, Wildlife & Parks. In other areas, the daily bag limit is 15 with no size restrictions. Always check local regulations.

Yellowstone Cutthroat Trout

The Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) is a prized game fish native to Montana. These trout have golden-brown bodies with prominent black spots near the tail and signature red-orange slash marks under the jaw. Yellowstone cutthroat trout average 10 to 15 inches and weigh under 2 pounds, although specimens pulled from larger rivers can reach 20 inches and weigh more than 3 pounds.

The best time for summer fly-fishing is during late morning and afternoon insect hatches on the upper Yellowstone River.
Bag limits and size restrictions for Yellowstone cutthroat trout vary significantly across Montana. In Yellowstone National Park and some other areas, all native cutthroat trout must be released immediately, while in other regions, limits typically range from zero (catch-and-release only) to three.