Flathead Catfish vs Blue Catfish – What’s The Difference?

Flathead and blue catfish share many similarities. For this reason many people ask about their differences, if any. Let’s answer, what is the difference between flathead catfish and blue catfish?

Flathead catfish and blue catfish are different catfish species and genus. Flathead catfish is the P. olivaris species and blue catfish is the I. furcatus species. Blue are found more south than flatheads near Belize and Guatemala in South America. Flathead is brown-yellowish color while blue is more slate blue.

This article will compare their tastes, textures, mercury levels, costs and whether one catfish can substitute for the other in recipes. In addition, I’ll compare their nutrients, habitats, species and appearance.

As a Certified Health Coach many of my clients ask about fish including catfish. In addition to coaching clients about them, I’ve purchased, researched and consumed both catfish prior to, during and sometimes after writing this article.

Flathead Catfish vs Blue Catfish: Habitats, Size, Weight and Appearance

There are times the same type of catfish are difficult to tell some species apart from the other. This may cause a slight problem when fishing, shopping or just because you’re curious. Therefore, let’s take a close look at their differences..

To tell the difference between a flathead catfish and a blue catfish check their tail fin and anal fin. Blue catfish have a forked tail fin while flathead has a slightly notched, unforked tail fin. Flathead’s anal fin is short and round with about 12 soft rays. Blue’s anal fin is longer with a straight edge and 30 to 36 soft rays.

Other ways to tell the difference:

Blue catfish has a slate blue colored body. Flathead has a brown to yellowish colored body mottled with dark colors.
The blue upper jaw protrudes more than the lower jaw. The flathead lower jaw protrudes more than the upper jaw.

Scientific Classifications, Families and Species

Blue catfish are from:

Family: Ictaluridae
Genus: Ictalurus
Catfish species: I. furcatus
Common nicknames: Channel cats, cats, hump-back blue.

Flathead catfish are from:

Family: Ictaluridae
Genus: Pylodictis
Catfish species: P. olivaris
Common nicknames: Mudcat, Shovelhead cat, yellow cat, Mississippi cat, pied cat.

Both catfish shown in the picture below, flathead differ greatly in appearance from blue.

Fishing? Where to Find and Catch Blue and Flathead

Blue

Blue cats are native to the Mississippi, Missouri and Rio Grande river basins. They range from The United States down south to Mexico, Belize and Guatemala.
They’re found in rivers, lakes, ponds and in some brackish water inlets. This is where to find catfish fishing.

Flathead

Flathead catfish are native to The United States, lower Canada and northeastern Mexico. They range from The Great Lakes, west of the Appalachian Mountains, south to the Gulf of Mexico and west to Texas.
They’re found in lakes, ponds, rivers and in some brackish water inlets.
The flathead prefers murky water with little to no flow around brush.
Flathead catfish prefer slow moving water.

Both catfish are from the same wildlife area and swim in similar waters. Although, catch blue more south in South America.

Colors

Blue catfish have a slate blue body fading to a silvery white belly.
Flathead catfish have a brown-yellowish body mottled with brown or black. The belly is pale white to creamy.

Fin Blue and Flathead

Dorsal Fin

Blue has one dorsal fin.
Flathead has one dorsal fin.

Anal Fins

Blue cats have one anal fin with 30 to 36 soft rays. The edge of the anal fin is straight.
Flathead cats have one anal fin with about 12 soft rays. The edge of the anal fin is rounded.

Tail Fin

Blue catfish have a forked tail fin.
Flathead catfish have a slightly notched, unforked tail fin.

Mouth

Blue cats have a wide mouth with their jaws meeting before the eye line. The upper jaw protrudes more than the lower jaw. Their mouth has four pairs of barbels or whiskers around the mouth.
Flathead cats have a wide mouth with their jaws meeting before the eye line. The lower jaw protrudes more than the upper jaw. Their mouth has four pairs of barbels or whiskers around the mouth.

The video does an excellent job comparing blue, flathead and channel catfish.

Scales

Blue catfish have soft skin with no scales.
Flathead catfish have soft skin with no scales.

Size and Weight

Blue cats average less than 24 inches but can grow up to 60 inches and weigh more than 100 pounds.
Flathead cats average 24 to 46 inches long but can grow up to 60 inches and weigh more than 100 pounds.

Lifespan

Blue catfish average lifespan is 9 to 10 years.
Flathead catfish average lifespan is 5 to 22 years.

Diet

Blue consumes the following:

Small fish
Frogs
Insects
Crabs
Mussels
Plants
Worms
Small crustaceans

Flathead consumes the following:

Plants
Insects
Eels
Worms
Grayfish
Blue crabs
Small crustaceans
Small fish

Species Resources¹²

Disclaimer: The Keto link below 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.

Catfish is 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.

Taste and Texture

Taste and texture are two reasons people choose to eat a certain catfish. After all, who wants to add a fried catfish fillet to their plate, unless they enjoy the taste? When comparing the two fish, let’s take a detailed look at the taste and texture of both.

Blue catfish and flathead catfish have a similar mild to medium taste. Blue and flathead may taste slightly muddy depending on the type of water or temperature it came from. The firm textures of both are less flakey than most other white catfish. A catfish farm raised will taste milder.

Therefore, a flathead from cleaner water will taste better than a blue from muddier water. In addition, a blue from cleaner water will taste better than a flathead from muddy water.

Blue cats have a mild to sweet flavor. If wild caught, the flavor may be fishy or muddy. The texture is meaty and moist if cooked properly.

Flathead cat has a mild to sweet taste and is good to eat. A farm raised catfish will be milder than the wild caught which will be more medium and slightly muddy. The texture is firm and moist if cooked properly.

To conduct some original research, I polled my readers and people from food groups. The following are the results from the poll of 49 people. I asked which fish tastes better?

52% preferred the taste of flathead catfish.
41% preferred the taste of blue catfish.
7% said they had no preference, or it depended where the fish was caught.

In the battle of catfish taste, flathead was found to taste better.

Find out how bullhead catfish and channel catfish mercury levels compared in my article here.

This video teaches you how to cook blue catfish.

Substitutions

It’s not always possible to locate the type of catfish called for in a recipe. In addition, maybe you caught one type or have only one in the refrigerator. Let’s take a close look at if you can substitute fish for the other.

Blue catfish and flathead catfish can substitute for each other in recipes due to their similar mild flavors. Both textures are firm and moist allowing them to be used as alternatives. Both fish can be prepared using similar cooking methods like frying, deep frying, baking, grilling or broiling.

Flathead substitutes include the following fish:

Blue catfish
Bullhead catfish
Channel catfish
Mackerel
Tuna
Bass
Grouper
Northern pike

Blue substitutes include the following fish:

Flathead
Bullhead
Channel catfish
Tuna
Mackerel
Northern pike
Bass
Grouper

How To Cook Blue Catfish and Flathead catfish

Blue Catfish

If the catfish is muddy or strong, try soaking in icy water or milk over night. Rinse and soak again. Many people like coating it with yellow cornmeal before frying or baking.

Popular cooking methods:

Deep frying
Frying
Baking
Grilling
Broiling

Flavor pairings:

Yellow cornmeal
Salt
Pepper
Lemon pepper
Lemon
Cajun
Creole seasoning
Mustard
Chili powder

The following video provides you with tips about how to remove the muddy taste from catfish.

Find out how channel catfish compared in my comparison article.

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.

Flathead Catfish

If the flathead is muddy or fishy, try these two popular methods to lessen the strong flavor:

Soak the catfish fillets in milk or icy water over night. Rinse and soak again. This helps extract the muddy flavor from the flesh.
Trim away all the darker flesh from the middle of the fillet or directly under the skin. The darker meat has the muddier flavor.

Popular catfish cooking methods:

Deep frying
Frying
Baking
Grilling
Broiling

Flavor pairings:

Yellow cornmeal
Mustard
Cajun
Lemon pepper
Creole seasoning
Chili powder
Black pepper
Lemon

The chef provides tips on how to cook catfish.

Mercury Levels

The FDA and EPA have issued suggestions and warnings regarding mercury levels in fish and how often they should be consumed. This is especially important for:

Developing children
Young infants
Pregnant women

They established a list of the following:

Best fish
Good choices
Fish to avoid

Since mercury can be harmful in greater amounts, everybody should be aware how much mercury each catfish contains.

Blue catfish and flathead catfish have similar levels of mercury and are listed on the FDA’s best choices 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 fish foods or changing your dietary habits.

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 fish recommendations³⁴.

Cost

The prices for catfish will vary depending on where they’re sold and how the fish are caught. Its a good idea to check the label to see if it’s farm-raised or wild-caught. This affects the price.

Blue catfish and flathead catfish have a similar price per pound. Both live blue and flathead costs $3.50 per pound. Catfish fillets price ranges from $16.00 to $34.56 per pound. Blue catfish fillets cost $18.99 per pound.

I conducted a search for the most popular websites selling catfish online. The following are the prices I was able to find in my search.

Kevin Garce checking prices of catfish and seafood in his local market. — Checking prices of catfish and seafood in my local market

I checked online at Amazon and found the following fish prices:

Wild Blue catfish fillet
- $18.99 per pound
Catfish fillets (doesn’t specify which type)
- $34.56 per pound

Check out Amazon’s current prices and selection of seafood, Fresh Seafood.

I checked Fulton Fish Market online:

Wild Channel catfish fillet
- $29.30 per pound

I checked Citarella online:

Catfish fillet (doesn’t specify type)
- $16.00 per pound

I checked FreshDirect online:

Farm raised Catfish fillets (doesn’t specify the type)
- $12.99 per pound

I checked Cast Away Lakes online and found live ones for sale:

Live flathead catfish
- $3.50 per pound
Live blue
- $3.50 per pound

Find out how channel catfish’s taste and mercury levels compared in my article here.

Nutrition

The table below is the nutrients contained in 4 ounces.

Nutrient	Blue Catfish, raw (4 Ounces)	Flathead Catfish, raw (4 Ounces)
Calories	110	130
Fat	3.0 g	3.1 g
Saturated Fat	1.0 g	1.1 g
Cholesterol	66 mg	68 mg
Protein	19 g	20 g
Sodium	50 mg	55 mg
Omega-3	0.53 g	0.57 g
B-6	0.1 mg	0.3 mg
B-12	2.4 mcg	1.9 mcg
Thiamin	0.22 mg	0.19 mg
Riboflavin	0.11 mg	0.08 mg
B5	0.9 mg	0.4 mg
Iron	0.3 mg	0.3 mg
Niacin	2.1 mg	2.9 mg
Folate	11.2 mcg	9.2 mcg
Potassium	404 mg	508 mg
Magnesium	26 mg	37 mg
Phosphorus	236 mg	293 mg
Calcium	20.3 mg	25.3 mg
Zinc	0.5 mg	0.6 mg
Selenium	14.2 mcg	17.2 mcg

Nutrient Sources⁵⁶⁷⁸

Examining the nutrients above, both contain a good amount of protein, omega-3 fatty acids, minerals and B vitamins. The numbers for each catfish typically is similar. Therefore, it’s difficult to say which one is healthier.

Blue catfish and flathead catfish are both healthy and provide a similar amount of protein, heart healthy omega-3 fatty acids, B vitamins, potassium, magnesium, phosphorus and selenium.

Keep reading the section below to find out how each of these nutrients is beneficial for health.

Health Benefits

Most fresh seafood, low in mercury, provide a great deal of health benefits. The nutrients contained in fresh fish benefit the body in many ways, especially omega-3 fatty acids. The nutrients and how they benefit the body is discussed below.

B Vitamins

The B vitamins provided by blue and flathead catfish include the following:

B1 (thiamin)
B2 (riboflavin)
B3 (niacin)
B5
B6
B9 (folate)
B12

B vitamins help support the following:

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

Omega-3 Fatty Acids

Of all the nutrients, omega-3 fatty acids may be the most important. Flatheads provides slightly more, 0.57 grams. Omega-3 fatty acids are healthy in many ways, especially for the heart.

They have been determined in scientific studies to help with the following:

Regulating heart rhythms.
Lowering inflammation.
Reducing triglycerides.
Maintain healthy blood pressure.
Lowering bad cholesterol.
Increasing good cholesterol.
Keeping the arteries healthy and functioning properly.

Since they are so beneficial, omega-3s are sold as a supplement. They are extracted from the flesh of fatty fish like salmon, cod livers, herring, anchovies, sardines and tuna. The best way to obtain omega-3 is consuming fresh fish, low in mercury twice per week.

Two of the fatty acids, DHA and EPA, have been shown in studies to lower blood pressure and improve the function of blood vessels ((National Center for Biotechnology: Marine Omega-3 Supplementation and Cardiovascular Disease)).

Other studies have shown them to reduce joint stiffness and pain in people with arthritis. Omega-3 fatty acids have also increased the effectiveness of anti-inflammatory drugs.

Catfish dinner with fries. — Catfish dinner with fries

Calcium

Flatheads provide a little more, 25.3 grams of calcium per four ounces. Calcium is important for the heart and blood pressure. Harvard Health reports calcium helps maintain blood pressure by helping in the controlling of the relaxing and tightening of blood vessels⁹.

Calcium also helps the following:

Helps muscles function properly.
Improve nerve function.
Build and maintain strong bones.

Potassium

Potassium helps the body get rid of excess sodium reducing fluid build-up. These help keep systolic and diastolic blood pressure lower ((American Heart Association: How Potassium Can Help Control High Blood Pressure)).

The more potassium, 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 water¹⁰.

According to Harvard Health, a number of studies have shown a connection between high blood pressure and low potassium levels¹¹.

Magnesium

Magnesium helps keep blood pressure levels stable and balanced.

A recent study researched previous studies and concluded magnesium supplementation decreased systolic and diastolic blood pressure¹².

Magnesium helps control the following:

Blood sugar
Blood pressure
Muscle
Insomnia
Nerve function

One reason many people supplement with magnesium in the evening is because it helps calm the whole body including blood vessels.

In the heart and muscles, 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 ((National Institutes of Health: Magnesium)).

Phosphorus

Phosphorus has been shown in scientific studies to help with the following:

Help the kidneys remove waste.
Help the body manage and store energy.
Promote healthy nerve conduction.
Promote teeth and bone strength.
Muscle contraction.
Muscle recovery.

Selenium

Flatheads provide 17.2 mcg of selenium per four ounces. Selenium is a nutrient which is not written about much in articles about health. Many scientific studies¹³ show selenium may help to protect the following:

Heart disease
The immune system
Cognitive issues
Thyroid

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