In the world of freshwater bass fishing, two species reign king: the Largemouth Bass and the Smallmouth Bass. While there are other types of bass (spotted, white, for example), Largies and Smallies are the most common targeted on the fly rod.

To the untrained eye, Largemouth and Smallmouth bass look very similar and some may confuse for the same fish. However, there are not only physical distinctness between the two species, there are behavioral differences that impact how we should target them. 

In this guide, we’ll examine the commonalities and differences in Largemouth and Smallmouth bass, delving into physical, behavioral, and angling differences between the species that will help you not only identify which type of bass you just caught, but also help you catch more of them.

The Science Behind Largemouth and Smallmouth Bass

Let’s harken back to our high school biology class and talk about how largemouth and smallmouth bass are scientifically classified. Don’t worry, we won’t get too nerdy here, but there are some interesting facts to learn. 

Both largemouth and smallmouth bass are members of the sunfish family (Centrarchidae), which actually means they’re both related to the common bluegill. They’re also both members of the black bass (Micropterus) genus, but after that, the differ in species. 

Largemouth bass have the scientific name “Micropterus salmoides” and smallmouth bass have the scientific name “Micropterus dolomieu”. The taxonomic similarities indicates that the two species evolved closely together. Additionally, they are both also oviparous (lay eggs, externally fertilized by the male), carnivorous (meat eating), and fun to catch on the fly rod (not scientific, but most important to us). Okay, science rant over. Let’s get into the cool stuff.

How to Identify Largemouth vs. Smallmouth

While largemouth and smallmouth possess similar underlying biology, the differ in size, color, and overall appearance. Once you understand the distinctive physical characteristics of the two species, you’ll instantly be able to tell which is which.

The most apparent difference between largemouth and smallmouth bass is their color. Largemouth bass are generally more green while smallmouth bass are significantly more brown in appearance. Largies have been appropriately dubbed “green bass” and smallies are often called “brown bass.” You’ll also hear smallies called “bronzebacks.”

While their different colors are a glaring feature of each bass, the size of their mouths (hence the names) are also different. Largemouth bass have, to the surprise of no one, large mouths and jaws that extend beyond their eyes. Smallmouth bass have, you guessed it, small mouths where the jaw is in-line with their eyes.

In addition to differences in their mouths and jaws, largemouth and smallmouth have distinctive patterns on their bodies. Largemouth have a noticeable horizontal stripe along the sides of their bodies, while smallmouth display vertical bars. Despite their differing appearance, both use these to help detect movement of prey in the water (more on that later). 

Finding Largemouth vs Smallmouth

Largemouth Bass Habitat

Largemouth bass are most assosicated with calm, water, heavily vegetated or wood-laden waters. Habitats with these types of features provide ideal cover and ambush points for largemouth to hunt there prey while being hidden from potential predators. 

Lakes, ponds, and slow moving parts of rivers provide the ideal habitat for largemouth bass. In these areas, vegetation like lily pads, submerged grass, and aquatic weeds tend to thrive, providing not only the structure largies like to associate with, but also the prey for largies to feast on.

Largemouth bass also can thrive in murky, at times dirty water. They possess a strong lateral line, which helps them sense movement in the water. Despite low water clarity, largies can sense their prey using these lateral line sensors which gives them an advantage over other predators in the water. 

Largies are also inclined to ambush their prey. They’re hunting style typically drives them to lie in wait among vegetation or wood, pause for their prey to unknowingly enter their realm, and strike. This is a big reason why largemouth bass like slow, heavily structured water- its suits their hunting and feeding styles.

Smallmouth Bass Habitat

In contrast to largemouth bass, smallmouth bass are associated with cooler, clearer waters with rocky structure. Smallmouth thrive in these conditions based on how they have evolved differently from their largemouth cousins.

Rivers, streams, and lakes with rocky shorelines provide the ideal habitat for smallmouth bass. While smallies have a lateral line similar to largemouth, they are more visual feeders. They’re more apt to see, then chase their prey as opposed to stalking and ambushing. 

Because of this hunting style, clear water is often a necessity for smallmouth bass. If you’re in a lake, smallmouth will typically find the coolest, clearest water they can while thriving in rivers, with plenty of access to cool, oxygenated water.

Catching Largemouth vs Smallmouth

Now we know where both largemouth and smallmouth like to live and we can target each one appropriately. But what about the type of fly gear for each? When fly fishing for largemouth and smallmouth, we use similar gear for each with some occasional differences, mostly in the weight rod and line that we use.

Gear for Largemouth

Rods and Reels for Largemouth Bass

When fly fishing for largemouth bass, anglers typically beef up their rods, using 7-9 weight rods. A rod with fast action and big backbone is essential to deal with larger flies and pulling largemouth out of cover. 

Pairing the rod with the appropriate line depending on the depth you are fishing is also a necessity. I personally spend most my largemouth fishing on small rivers and ponds, so a floating line fulfils most needs. If a fly requires a sinking line to pull under the water or we need to be deeper in the water column, an intermediate line or a versileader gets the job done. 

For reels, don’t overthink it. A sturdier reel with a quality drag system is all you need. Largemouth are powerful, but don’t go on big, long runs so the focus (and money) should be spent on a quality rod and line. 

Flies for Largemouth Bass

Large, bulky flies imitating baitfish, crawfish, and frogs should be in every largemouth bass fly box. Largemouth are opportunistic feeders, so “matching the hatch” isn’t as vital as it is in trout fishing. 

Stock your box with Clouser minnows, gamechangers, poppers, Wooly Buggers, or any minnow/crayfish fly you can think of. Finding largemouth and making your fly look edible is more important than selecting the perfect fly. Make it look like food!

Gear for Smallmouth

Fly gear for smallmouth is very similar to the gear needed for largemouth bass. Essentially, the rod, reel, and flies are very similar, just downsized to reflect the typically smaller size of smallmouth (and their mouths).

For more on fly fishing gear for smallmouth bass, check out Smallies on the Fly.

Rods and Reels for Smallmouth Bass

For smallmouth, 5-7 weight rods will get the job done, with the best overall weight being a 6 weight. These rods provide enough power to throw bass flies and are light enough to carry around all day with ease. Fast-action rods are preferred, as you’ll be throwing nearly all streamers and poppers. Cutting through the wind with these sometimes bulky flies is an important factor in smallmouth fishing.

Similar to largemouth fishing, a floating line will take care of the majority of your needs. Sinking lines or versileaders are really only necessary if you have a buoyant fly that needs to get under the water, or you need to get your flies down deeper. 

For reels, similar to largemouth fishing, any quality reel will have more than enough stopping power for smallmouth. Smallmouth are a little more lively than their largemouth cousins and could go on powerful runs, especially if they get into the current of the river they inhabit. Most modern reels have plenty of drag to combat this, so don’t overthink which reel you pick.

Flies for Smallmouth Bass

Again, similar to largemouth, smallmouth bass are not that picky when it comes to their forage. They are also opportunistic feeders that are willing to attack minnows, crayfish, and frog patterns.

The only difference is when selecting flies for smallmouth is to slightly size down your selections. Smallmouth are generally smaller and don’t have the bucket-sized mouths of largemouth, so smaller patterns generally perform better. That doesn’t mean that we should be throwing size 22 zebra midges, but maybe that 7 inch gamechanger you have for largemouth doesn’t get munched on.

Conclusion

While largemouth and smallmouth bass may share some many similar characteristics, their distinct preferences for different environments reflect their unique evolutionary adaptations and behaviors. By understanding the habitat preferences of each species, you can effectively target largemouth and smallmouth bass in their respective environments, enhancing your chances of getting hooked up.

Also, now you’ll be able to identify what you have just caught with the distinctive features of largies and smallies!

When fishing for largemouth, use stouter gear and large flies. When fishing for smallmouth, downsize your gear. It’s as simple as that!

Which do you prefer to target, largemouth or smallmouth?