Rock Bass vs Largemouth Bass – What’s The Difference?

Largemouth bass and rock bass have many similarities. For this reason many people ask about their differences. Let’s answer, what is the difference between a largemouth bass and a rock bass?

Largemouth bass and rock bass are different species although from the same family. Rock bass is the A. rupestris species, largemouth bass is the M. salmoides species. Largemouth bass has a stronger, fishier flavor than rock bass. Largemouth bass contains more mercury and costs more than rock bass.

This article will compare their tastes, textures, cooking methods, costs, mercury levels and whether one can substitute for the other in recipes. In addition, I’ll do a side-by-side comparison of their habitats, size, weight and nutritional values.

Keto Bread Tip: Great News! Did you know, you don’t have to give up your favorite bread, pizza or sandwiches to follow a 100% Keto diet. Find out more in the KetoBreads website by clicking here, Keto Breads.

Disclaimer: The above link and others in this article are affiliate links which means I may earn a small commission at no extra cost to you. As an Amazon associate I earn from qualifying purchases.

Rock Bass vs Largemouth Bass: Habitats, Size, Weight and Appearance

How can you tell the difference between a rock bass and a largemouth bass?

The easiest way to tell the difference between a rock bass and a largemouth bass is their body markings, shape and dorsal fin. Largemouth bass have a thicker, longer body compared to the flatter rock bass. Largemouth bass have two dorsal fins, rock bass have one. Largemouth bass have one blotchy, jagged lateral line. Rock bass have multiple black spotted lateral lines.

Other ways to tell the difference between a rock bass and a largemouth bass:

  • Rock bass have a tear drop shaped marking under their eyes largemouth bass doesn’t have.
  • Largemouth bass upper jaw reaches past the eye line. Rock bass jaw doesn’t reach the eye line.
  • Rock bass have red or orange eyes. Largemouth bass have darker eyes.
  • Adult largemouth bass average 16″ long. Adult rock bass average 6″ to 10″ long.

Rock Bass and Largemouth Bass Scientific Classifications, Families, Species

Rock bass are from:

  • Family: Centrarchidae
  • Genus: Ambloplites
  • Species: A. rupestris
  • Common nicknames: Red eye, rock perch, goggle eye.

Largemouth bass are from:

  • Family: Centrarchidae
  • Genus: Micropterus
  • Species: M. salmoides
  • Common nicknames: Green bass, bigmouth bass, largies, bucketmouth.

Rock Bass and Largemouth Bass Habitats

Rock Bass

  • Rock bass are native to North America and can be found from Canada down to Florida and west to Texas. They are mostly found in the eastern and central United States.
  • Rock bass are found in streams, ponds, lakes and rivers.
  • Rock bass prefer rocky shorelines and vegetation areas. They can be found under docks and near swimming areas.

Largemouth Bass

  • Largemouth bass are native to the eastern and central United States, southeastern Canada and northern Mexico. They have been introduced into many other areas as well.
  • Largemouth bass are found in streams, ponds, creeks, lakes and rivers.
  • Largemouth bass prefer warmer waters and murky waters with vegetation. They use logs and similar items as protection.
rock bass and largemouth bass photo comparison
top Rock bass<br >bottom Largemouth bass

Rock Bass and Largemouth Bass Appearance

Rock Bass and Largemouth Colors

  • Rock bass have an olive green to golden brown upper back and sides fading down to a silvery, white belly. Rock bass have black spots which form broken lateral stripes down the body. The eyes are red.
    • Rock bass have the ability to change colors to match their surroundings for protection.
  • Largemouth have an olive green and gray upper back and body which fades lighter on the sides a white belly. They have dark blotches forming a staggered, horizontal line down the body.

Rock bass have multiple black spotted lateral lines running down the body. Largemouth bass have one dark, blotchy, staggered lateral line running down the body.

Dorsal Fins

  • Rock bass has one dorsal fin with 10-13 spines and 11-13 rays.
  • Largemouth bass has two dorsal fins. The front dorsal fin has 9 spines, and the rear dorsal has 12-13 soft rays.

The rock bass has one dorsal fin with spines and soft rays. The largemouth bass has two dorsal fins, the front with spines and the second with soft rays.


  • The rock bass mouth is large but doesn’t extend past the eye line. The rock bass mouth doesn’t curve upward.
  • The largemouth bass mouth is large, wide, and the jaw extends past the eye line. The mouth is protruding and doesn’t curve upward.

Both rock bass and largemouth bass have teeth inside their mouths.

Distinguishing Marks

  • Rock bass has red eyes and rows of dark spots forming lateral lines down the body. Rock bass has a dark tear drop below their eye.
  • Largemouth bass has dark blotches on its side forming a jagged horizontal line down the body.

Rock bass have red eyes compared to largemouth’s darker eyes.

Body Shape

  • The rock bass body is flat and is slightly elongated.
  • The largemouth body have a slender, fusiform (torpedo shape) body shape.

The largemouth’s body is slender, not as flat and longer than the rock bass.

Rock Bass and Largemouth Bass Size and Weight

  • Rock bass average 6-10″ long and weighs about 1 pound.
  • Largemouth bass average 15″ long and can weigh up to 20 pounds.

Largemouth bass on average weigh more and are longer than rock bass. Largemouth females weigh more than males the same age.

Rock Bass and Largemouth Bass Lifespan

  • Rock bass lives up to 8-10 years.
  • Largemouth bass lives up to 10-16 years.


Rock bass consume the following:

  • Insects
  • Worms
  • Smaller fish
  • Minnows
  • Small crustaceans

Largemouth bass consume the following:

  • Insects
  • Small fish
  • Bluegill
  • Minnows
  • Yellow perch
  • Worms
  • Snails
  • Frogs
  • Crayfish
largemouth bass and rock bass photo comparison
top Largemouth bass<br >bottom Rock bass

In a recent article I compared rock bass to crappie. Find out how these similar sunfish compared in my article, Rock Bass vs Crappie – What’s The Difference? Let’s Compare.

Species Resources 1 2 3 4 5 6 7 8 9 10 11 12

Rock bass, largemouth bass and other fish are renowned for being a part of many diets like keto or heart healthy.

If you’re eating low-carb or want to give keto a try, many of my clients have followed this 28-Day Keto Challenge with great success. Visit their website and check it out.

Rock Bass and Largemouth Bass: Tastes and Textures

One of the most important things people takes into consideration when choosing a fish is its taste. When comparing the two fish, does rock bass taste like largemouth bass?

Rock bass has a mild to sweet taste compared to largemouth’s stronger, fishier taste. Largemouth bass may have a fishier flavor depending on the water it was caught in. Rock bass and largemouth bass have a firm texture and a little flakey. 

What does largemouth bass taste like? Largemouth bass has a strong taste and fishy flavor. Depending on the water it was caught in the fishiness may be stronger. The white flesh has a firm, meaty texture.

Is rock bass fish good to eat? Rock bass is good to eat. Most people are pleased with the mild taste. The flesh is slightly firm and flakey.

I polled many of my readers and members of food groups I belong to. The following are the results of my poll which consisted of 35 people. I asked which fish tasted better, largemouth or rock bass?

  • 69% preferred the taste of rock bass.
  • 23% preferred the taste of largemouth.
  • 8% said they liked both fish the same.

Bluegill is another sunfish like rock bass. In my recent article find out which one tasted better in my poll of readers, Rock Bass vs Bluegill – What’s The Difference? We Compare.

Rock Bass and Largemouth Bass Substitutions

When preparing recipes for dinner it’s not always possible to locate the type of fish called for. If you have some rock bass or largemouth bass, you may ask, can I substitute largemouth bass for rock bass?

Largemouth bass is not a suitable substitute for rock bass due to its stronger taste and fishier flavor. Although they have similar textures, rock bass fillets are smaller than the largemouth bass fillets. This makes them unsuitable for a largemouth bass recipe requiring a larger size fillet. 

Rock bass substitutes:

  • Bluegill
  • White crappie
  • Black crappie
  • Pumpkinseed
  • Green sunfish
  • Lake herring
  • Tilapia
  • Pollock

Largemouth bass substitutes include the following:

  • Salmon
  • Bluefish
  • Tuna
  • Black Sea bass
  • Mahi Mahi
  • Walleye

Find out if smallmouth bass can substitute for largemouth bass in my article, Smallmouth Bass vs Largemouth Bass: What’s The Difference? Also, find out if their mouths really different?

How To Cook Rock Bass

Popular ways to cook rock bass are:

  • Deep frying
  • Pan frying/stir fry
  • Baking
  • Grilling

Flavor pairings for rock bass:

  • Cayenne pepper
  • Black pepper
  • Cajun
  • Tarter sauce
  • Beer batter
  • Bread crumbs
  • Crackers
  • Parmesan cheese
  • Lemon juice
  • Brown sugar

How To Cook Largemouth Bass

Frying largemouth bass indoors can create a fishy smell which many people dislike. By adding many of the spices below can help lessen the fishy smell or taste. In addition, removing the skin and bloodline before cooking will help with the fishy taste.

Largemouth can be baked, broiled, deep fried, grilled and sautéed.

Largemouth flavor pairings:

  • Garlic
  • Paprika
  • Black pepper
  • Lemon
  • Olive oil
  • Dill
  • Mustard

Smallmouth bass have a different taste than largemouth bass. Find out how rock bass compared to them in my article, Rock Bass vs Smallmouth Bass – What’s The Difference?

How Much Rock Bass and Largemouth Bass Costs

The costs for fresh fish will vary depending on how the fish are caught. When purchasing any fish, be sure to check the label to see if it is wild-caught or farm raised. Therefore, which is more expensive, rock bass or largemouth bass?

Largemouth bass is more expensive than rock bass. The average cost for sunfish fillets is $16 to $22 per pound. Live largemouth bass cost $1.25 per 2-3″ fish. The average live sunfish averages $0.75 to $1 per 3-4″ fish. 

I checked online at Walleye Direct and found the following prices:

  • Wild, crappie fillets (sunfish)
    • $22.00 per pound

Seafood Markets:

  • Wild, sunfish fillets (does not specify which kind of sunfish)
    • $18.00 per pound

Dixon Fisheries:

  • Bluegill fillets (sunfish)
    • $14.95 per pound

For stocking ponds, Pond King has the following price per fish:

  • Black crappie – $1.00 per 3-4″ fish
  • Bluegill – $0.75 per 3-4″ fish
  • Hybrid bluegill (green sunfish x bluegill) $0.75 per 3-4″ fish
  • Largemouth bass – $1.25 per 2-3″ fish

Rock Bass and Largemouth Bass Nutritional Values

Largemouth bass and rock bass are excellent sources of protein, healthy fats, minerals and B vitamins. Both sunfish fish contain the following:

  • Omega-3 fatty acids
  • Niacin
  • Folate
  • Potassium
  • Magnesium
  • B6
  • B12
  • B5
  • Thiamin
  • Riboflavin
  • Iron
  • Selenium
  • Calcium
  • Zinc

Fresh water bass provides the following number of nutrients per four raw ounces:

Nutrient Freshwater bass
(4 ounces, raw)
Calories 129
Fat 4.2 g
Saturated fat 0.9 g
Cholesterol 77 mg
Protein 21 g
Omega-3 0.77 g
B-6 0.1 mg
B-12 2.2 mcg
Thiamin .08 mg
Riboflavin .08 mg
B-5 0.8 mg
Niacin 1.4 mg
Folate 17.0 mcg
Iron 1.6 mg
Potassium 403 mg
Magnesium 34 mg
Phosphorus 226 mg
Calcium 90.7 mg
Zinc 0.7 mg
Selenium 14.2 mcg

Nutrient Resources 13 14 15 16

Largemouth bass and rock bass provide a similar percentage of the same nutrients, except for omega-3 fatty acids. Freshwater bass provides 0.77 g while most smaller sunfish, like rock bass, provide approximately 0.16-0.29 g per 4 ounces.

Keep reading the next section below to find out how the nutrients benefit health, especially omega-3s.

In this article I compared smallmouth to spotted bass. Find out their differences, Spotted Bass vs Smallmouth Bass: What’s The Difference?

Rock Bass and Largemouth Bass Health Benefits

Omega 3 Fatty Acids

The omega-3 fatty acids contained in largemouth bass and rock bass help keep arteries healthy and are considered heart healthy. The omega-3s may help with the following:

  • Lowering triglycerides.
  • Reduce inflammation.
  • Reduce plaque buildup.
  • Keeping bad cholesterol low.
  • Keeping good cholesterol high.
  • Help keep the heart rhythms more normal.

DHA and EPA, two of the fatty acids, are associated with lowering blood pressure and improving the health of blood vessels 17.

Studies suggest omega-3s can help reduce joint pain and stiffness in people with rheumatoid arthritis. They may also boost the effectiveness of anti-inflammatory drugs.


Largemouth bass and rock bass provide approximately 34-39 mg of magnesium per four ounces. It calms and relaxes the whole body including blood vessels. Magnesium has been shown to help improve sleep related problems like insomnia 18.

Magnesium helps keep blood pressure levels balanced and stable. A recent study researched 22 studies and concluded magnesium supplementation decreased diastolic and systolic blood pressure 19.

Magnesium helps control muscle and nerve function, blood sugar and blood pressure.

In the muscles and heart, magnesium competes with calcium to help the muscles relax after contracting. When the body is low in magnesium, calcium can over stimulate the heart muscle’s cells causing a rapid or irregular heartbeat.

B Vitamins

The B vitamins provided by largemouth bass and rock bass include B1 (thiamin), B2 (riboflavin), B3 (niacin), B9 (folate) B6, B12 and B5. B vitamins help support the following:

  • Digestion.
  • Brain function.
  • Energy levels.
  • Red blood cells.
  • Cardiovascular disease.
  • Nerve function.


Largemouth bass and rock bass provide approximately 85-90 mg of calcium per four ounces. Calcium is important for blood pressure and the heart. Harvard Health reports calcium helps maintain blood pressure because it helps to control the relaxing and tightening of blood vessels 20.

Calcium also helps the following:

  • Build and maintain strong bones.
  • Muscles need calcium to function properly.
  • Improve nerve function.


Largemouth bass and rock bass provide approximately 357-400 mg. Potassium helps the body get rid of excess sodium which helps reduce fluid build-up. These help keep systolic and diastolic blood pressure lower 21.

The more potassium you consume, the more sodium your body will lose. Consuming too much sodium or not enough potassium throws off the delicate balance the kidneys need to remove the excess water 22.

According to Harvard Health, a number of studies have shown a connection between low potassium levels and increased blood pressure 23.


Largemouth bass and rock bass provide approximately 203-259 mg of phosphorus per four ounces. It has been shown in scientific research to help with the following:

  • Promote healthy nerve conduction.
  • Aides the kidneys in waste removal.
  • Promote teeth and bone strength.
  • Muscle recovery after exercise.
  • Muscle contraction.
  • Help the body store and manage energy.


There are 13-14.2 mcg of selenium per four ounces of largemouth bass and rock bass. Many people don’t write about the benefits of selenium. I’m unsure why because many studies 24 show selenium may help to protect the following:

  • The immune system
  • Thyroid
  • Cognitive issues
  • Heart disease

Rock Bass and Largemouth Bass Mercury Levels

The EPA and The FDA have issued suggestions and warnings about mercury levels in fish and how often they should be consumed 25. This is especially important for young infants, pregnant women and developing children.

They established three lists:

  1. Best fish
  2. Good choices
  3. Ones to avoid

Therefore, does largemouth bass or rock bass have more mercury?

Largemouth bass have more mercury than rock bass. Freshwater bass has been listed on some states advisory warnings for high levels of mercury. Rock bass is one of the FDA’s best choice of fish regarding mercury levels.

If you’re pregnant, breast feeding or has a young child, Always check with a physician prior to eating new foods or changing your dietary habits.

These mercury warnings can change over time or affect only a particular area or state. Please check with your local EPA and FDA for the current recommendations 26.


Will a largemouth bass eat rock bass?

An adult largemouth bass will eat a smaller rock bass. Largemouth bass consume many smaller fish including sunfish like rock bass. Largemouth bass can consume fish up to approximately 50% of its body length.

Read Next – More SunFish vs SunFish Articles!

Spotted Bass vs Largemouth Bass: What’s The Difference?

Bluegill vs Redear Sunfish – Are They The Same? We Compare

Black Crappie vs White Crappie – What’s The Difference?

Bluegill vs Pumpkinseed – Are They The Same? Let’s Compare

Bluegill vs Redbreast Sunfish – What’s The Difference?

Article Resources: Foods For Anti-Aging follows strict guidelines to ensure our content is the highest journalistic standard. It's our mission to provide the reader with accurate, honest and unbiased guidance. Our content relies on medical associations, research institutions, government agencies and study resources. Learn more by reading our editorial policy.
  1. Wikipedia: Rock bass[]
  2. Rock Bass[]
  3. USFWS National Digital Library: Rock bass[]
  4. Minnesota Department of Natural Resources: Rock bass[]
  5. West Virginia Department of Natural Resources: Rock Bass[]
  6. Minnesota Department of Natural Resources: Sunfish biology and identification[]
  7. The Department of Natural Resources: Sunfish[]
  8. Wikipedia: Largemouth bass[]
  9. Wikipedia: Bass (fish) []
  10. U.S. Fish & Wildlife Service: Largemouth bass[]
  11. Texas Parks & Wildlife: Largemouth Bass (Micropterus salmoides) []
  12. Texas Parks & Wildlife: Bass Comparison and Identification[]
  13. Nutrition Value: Fish, raw, mixed species, fresh water, bass[]
  14. NutritionData: Fish, bass, fresh water, mixed species, raw[]
  15. The Topeka Capital-Journal: Keto, Paleo or Atkins diet? Hunting, fishing can help trim your waistline in 2020[]
  16. Nutritiondata: Fish, sunfish, raw[]
  17. National Center for Biotechnology: Marine Omega-3 Supplementation and Cardiovascular Disease[]
  18. National Institutes of Health: Magnesium[]
  19. National Center for Biotechnology Information: Effect of magnesium supplementation on blood pressure: a meta-analysis[]
  20. Harvard Health: Key minerals to help control blood pressure[]
  21. American Heart Association: How Potassium Can Help Control High Blood Pressure[]
  22. National Center for Biotechnology Information: The Effect of the Sodium to Potassium Ratio on Hypertension Prevalence: A Propensity Score Matching Approach[]
  23. Harvard Health: Potassium lowers blood pressure[]
  24. National Institutes of Health: Selenium[]
  25. FDA: Advice about Eating Fish[]
  26. National Center for Biotechnology Information: Mercury accumulation in largemouth bass (Micropterus salmoides) in a Florida lake[]

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