Haddock vs Cod – 5 Main Differences Explained

Written by Rebecca Bales
Updated: October 27, 2023
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Haddock and cod are both very popular white fish. Similar in body and nutrition, and about equally affordable, there are nonetheless some differences in appearance, flavor, and nutrients. The main physical differences are in their colors, size, body shape, front dorsal fins, and lateral lines, while there are a few differences in flavor and when they are best to eat.

Then one may wonder if the favoring of one fish over the other is simply a matter of tradition or personal preference. Why do fish and chips in some places use haddock, while others use cod? Does it really make a difference when you drown it in sauce? Which one holds up better to grilling? How are they substituted or interchangeable for one another? Let’s go over all these questions below!

The 5 Key Differences Between Haddock and Cod

Haddock vs Cod: Physical features

Right away, the easiest way to tell cod from haddock is their color. Cod is speckled green-brown or grey-brown. Haddock is grey or black with scales coated in mucus, plus a dark blotch above the pectoral fin (called St. Peter’s mark, Devil’s thumbprint or simply thumbprint). Cod has bigger, fatter, and thicker fillets, making it slightly costlier due to having more meat.

It can grow up to 40 in (1 m) or more in length and on average weighs 11-26lbs (5-12kg), with a record of 220lbs (100kg). The much smaller haddock is 35-58cm and even up to 112cm, but usually doesn’t reach more than 31 in (80 cm). It usually weighs 1-5lbs but can reach up to 37lbs. Cod also has equally long dorsal fins with a rounded front dorsal fin.

Haddock has a long, pointed front dorsal fin. Both have lateral lines, but whereas cod has a pale cream or white line, haddock has a black or dark grey line.

 Cod fillets are thicker and firmer. They’re great for grilling or searing because they don’t overcook as easily. Haddock fillets are thinner and more fragile.

Haddock vs Cod: Taxonomy

Both of these whitefish species are in the true cod family Gadidae, also called the cods or codfishes, but that’s where the similarities end. The type genus for cod is Gadus with 4 species being the Atlantic cod, Pacific cod, Greenland cod, and Alaska pollock (also called walleye pollock, snow cod, or bigeye cod). Haddock is a member of the genus Melanogrammus which contains the single species aeglefinus.

Haddock vs Cod: Commercial use

The difference in flavor between these two white fish is subtle, making them easily interchangeable with one another as well as with plaice and flounder. Instead, the biggest difference is in their texture, best cooking techniques or uses, and the ideal time to eat after catching them. Salted codfish is a popular dish in Spain, Portugal, the Caribbean, and Scandinavia.

Cod is one of the fish used for making imitation crabmeat. It is more versatile than haddock, handles grilling and searing, and is best eaten a few days after being caught. Both cod and haddock are two of the several fish used for making fish and chips, which originated in England. However, haddock is commonly eaten fresh, frozen, smoked, or dried, and is ideal for frying due to cooking more quickly.

Haddock vs Cod: Nutrients

Cod is higher in vitamins C, E, D, B1, B5, magnesium, potassium, calcium, iron, zinc, and calories than haddock. Due to the abundance of vitamin D in cod liver oil, it is an old remedy for rickets, arthritis, and constipation.

Haddock is higher in vitamins A, B12, B6, B3, proteins, 9 essential amino acids, phosphorus, and choline, but has no vitamin C. Both have equal amounts of vitamin B2, vitamin K, omega-3 polyunsaturated fatty acids, and are good sources of low-fat protein alternatives to red meat, with 3% fat and 97% protein; a 100g serving of cod has 17g protein and haddock has 20g. Both lack vitamin B9 (folate).

Overall, cod has more vitamins, haddock is slightly richer in minerals, and has more of the 9 essential amino acids tryptophan, leucine, lysine, threonine, isoleucine, methionine, phenylalanine, valine, and histidine.

Haddock vs Cod: Fisheries

Haddock is caught in the North Atlantic Ocean and Cod in the Atlantic and Pacific Oceans, with the more savory Pacific cod having the strongest global demand over the sweeter-tasting Atlantic cod. Due to the overlap in habitat, haddock is often caught in mixed-species fisheries with cod and other fish. Although haddock is more popular in certain regions cod is overall more popular due to its being more cost-effective and substantial, with a cleaner flavor for fish and chips. On the other hand, overfishing in the North Atlantic has made it necessary to catch more substitutes for Atlantic cod, including haddock.

Haddock vs Cod: Availability

Both haddock and cod are listed as vulnerable fish. In the UK, where fish and chips is a staple of its citizens’ diets, numbers have been dwindling for some time. Because there are fears, not only of a fish shortage, but also of job loss, the WWF (World Wide Fund for Nature) has listed them as endangered. The reason–over-fishing and global warming. Cod thrive in cold waters, and with the temperature of the North Atlantic Ocean rising, the ability of cod to spawn has been hampered. And haddock fish, on average, are smaller than in the past because the older classes of fish have been caught.

Bonus: What Do Haddock vs Cod Eat?

Animals that reproduce asexually – marble crayfish

Both haddock and cod feed on crustaceans like crayfish.

©Geza Farkas/Shutterstock.com

Both haddock and cod are carnivorous fish. Haddock rely on a diet of bottom-dwelling animals like worms, crustaceans, mollusks, sea urchins, sea stars, sand dollars, and fish eggs. Some adults also eat small fish like herring.

Codfish eat small baitfish, crustaceans, crabs, lobster, haddock, mackerel, mussels, mollusks, sand eels, squid, whiting, and worms. Cod can also be cannibalistic, with adults feeding on younger, smaller codfish.

Summary of Haddock vs Cod

Size & body shapeBigger, fatter, thicker filletsSmaller, thinner, flatter fillets
ColorSpeckled green-brown or grey-brownDark grey or black
Dorsal finsRounded front dorsal fin; equally long dorsal finsTall, pointed front dorsal fin
Lateral linesLightDark
TaxonomyGadidae family of true cod; genus Gadus; 4 speciesGadidae family of true cod; genus Melanogrammus; 1 species
Flavor & textureFirmer, dense, flaky white flesh, mild, cleaner flavor; Atlantic is sweeter while Pacific is more savoryFishier and more tender, flakier white flesh, lightly sweet
NutrientsHigher in vitamins and caloriesHigher in minerals, protein, and 9 essential amino acids
Best to eatTastiest a few days after being caughtBest eaten very fresh
CostSomewhat more expensive than haddockLess expensive than cod
Market & cuisineFish and chips, imitation crab, salted codfish; cod liver oil; versatile, good for grillingFresh, frozen, smoked, or dried; fish and chips; ideal for frying
HabitatThe Atlantic Ocean and the Pacific OceanNorth Atlantic Ocean
Substitute for or withHaddock, pollock, black cod, plaice, striped bass, hake, mahi mahi, grouper, tilapia, flounderCod, plaice, halibut, sole, flounder

The photo featured at the top of this post is ©

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About the Author

Rebecca is an experienced Professional Freelancer with nearly a decade of expertise in writing SEO Content, Digital Illustrations, and Graphic Design. When not engrossed in her creative endeavors, Rebecca dedicates her time to cycling and filming her nature adventures. When not focused on her passion for creating and crafting optimized materials, she harbors a deep fascination and love for cats, jumping spiders, and pet rats.

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