Fish in Dog Food - Dog Nutrition DB

In this article, we will explore all about fish in dog food. What fish ingredients are used by pet food manufacturers and what can you learn about their nutritional value and safety?

Contents

About Fish in Dog Food

Fish-based dog food is a great option for pet owners who want to ensure that their dog’s diet is both flavorful and nutritious.

Fishery ingredients include a variety of fish and fish products. While some fish species are rarely used in dog food, other ingredients such as fish meal or fish oil are more common.

Fish can be a little more expensive than some other animal-souced ingredients, but also provides lots of additional benefits.

Fishery ingredients make up 2.3% of ingredient tonnage but 12.9% of ingredient value.
Pet Food Production and Ingredient Analysis 2020^[4]

Nutritional Benefits of Fish

Fish is an excellent source of protein and is rich in omega-3 fatty acids, which are essential for a dog’s overall well-being.

Not only can fish provide a novel protein source for dogs, but it can also the omega-3 fatty acids found in fish can reduce inflammation, and support healthy skin and coat.

Overall, dog food with fish in it can be highly nutritious and palatable for dogs. Fish is included in many commercial dog foods.

Here are some of the reasons why:

High-Quality Protein

Fish is a high-quality protein source that is easily digestible for dogs. Fish protein provides a plethora of essential amino acids.

More specifically, fish contains lots of the amino acids that other protein sources are lacking such as methionine.

This makes fish a great supplemental protein to balance out the amino acid profiles of dog food recipes.

If that’s important to your dog:

Fish like herring, anchovies, sardines, or mackerel can be high in purines while most fish only contain a moderate amount.

Omega-3 Fatty Acids

Some fish, such as salmon, can be high in calories and used as a great source of energy.

Naturally, fish is low in carbohydrates but rich in fat and protein. And the fatty acids profile of fish is low in saturated fats.

Instead, many fish are rich in omega-3 fatty acids, which are essential for a dog’s growth and development. These fatty acids are important for vision and brain development in puppies.

Omega-3 fatty acids also have anti-inflammatory properties, which can be beneficial for dogs with certain health conditions.

Vitamins and Minerals

Fish is a natural source of many vitamins and minerals that are important for a dog’s overall health.

Fish is a good source of selenium, iron, zinc, iodine, magnesium, and potassium and fish bone can provide lots of calcium and phosphorus.

The fish liver is rich in vitamins A and D. Whole fish can be a good source of B vitamins such as folic acid, pantothenic acid, or B₁₂.

Is Fish Safe For Dogs?

Overall, fish products are highly regulated by the authorities^[19]. However, there are some possible downsides to eating fish:

Some fish, especially those higher up in the food chain like tuna, can expose dogs to mercury and methylmercury, a particularly toxic form of mercury.

But to be fair, the majority of fish-including pet foods have mercury concentrations well below suggested levels.

A 2021 study found some fish-based pet foods to be high in methylmercury but still at safe levels.

But a small number of foods tested in this study had concentrations above the suggested intake levels^[15].

So there is a small risk of chronic exposure to pollutants such as mercury or even dioxins or polychlorinated biphenyls (PCBs) if you feed the same product every day for years.

Obviously, this is a concern for dog owners because we know so little about safe consumption levels of mercury in dogs. And different sources suggest different safe limits for pet food.

But the authors could not confirm one single ingredient as the major or only source of mercury in commercial pet foods.

Another problem is that fish meal and fish oil are very prone to oxidation because they are so high in unsaturated fatty acids.

They are commonly treated with synthetic antioxidants such as ethoxyquin, butylated hydroxytoluene (BHT) or butylated hydroxyanisole (BHA) which are very effective at their job but also potentially harmful and controversial ingredients.

Fish meal is often fed to fish in aquacultures such as Atlantic salmon. This leads to some farmed fish accumulating preservatives and their metabolites such as ethoxyquin dimer which indirectly end up in human and pet food^[10].

In summary…

Feeding fish to dogs is good, but should be done in moderation.

Overall, fish is considered a safe ingredient that provides lots of nutritional benefits. And at this point, there is no reason to avoid specific seafood ingredients.

However, it may be a good idea to minimize feeding the same fish-based ingredient or product every day and to opt for diet rotation to avoid chronic exposure to contaminants.

Types of Fish Ingredients

The fishing industry produces immense amounts of fish waste each year, e.g. cannery waste, discarded or undersized fish, or parts not attractive for human food^[1].

So there’s plenty left for dog food manufacturers to choose from like trimmings, skin, fins, bones, fish heads, viscera, or scales.

Fresh Fish

Whole fish, deboned fish or fish parts are common in dog food.

The most widely used ingredients seem to be salmon, whitefish, tuna, cod, ocean fish, mackerel, sole, anchovies, and seabass^[4].

Manufacturers can choose between farmed or wild-caught fish.

Not all fresh fishery ingredients get properly labeled.

Ocean fish can include about any marine species. You can’t be sure if this ingredient was sourced for its nutritional value or because it was the least expensive (by-)catch of the season.

Whitefish is a fisheries term for species with light flaky flesh such as cod, haddock, whiting, pollock, or hake. These fish live near the seafloor and are less oily compared to pelagic plankton feeders.

In general, many of the edible fish are sold under generic names that are in many cases actually used for a group of similar fish. In other words, there is not just one “salmon”, “tuna” or “sardine”.

The FDA’s seafood list can provide some inside into which fish can be sold under certain commercial names or synonyms.

Fish By-Products

Whenever fish is filleted or canned, there are lots of unused leftovers. By-products include all the trimmings and fish viscera such as gills, heart, liver, spleen, stomach, and intestines^[1].

Think of the tails, heads, offal, guts, frames, blood, fins, skin, and bones that are left over after cutting just the two fillets from a fish.

These waste materials can make up to 30-70% of a fish’s fresh weight but are not commonly used in human food. They are often discarded despite being packed with nutrients.

Rendering by-products into fish meal or selling them to pet food manufacturers, for example, helps the fisheries industry to reduce waste. But of course, fish by-products can vary greatly in their composition and nutritional quality^[6].

Fish Meal

Overall, fish meal is a valuable ingredient used in very many dog food products, providing lots of nutritional benefits.

Fish meal is made from ground and cooked fish that has been partially defatted and processed into a dry protein powder.

The fish or by-products used to make fish meal can come from a variety of sources, they often include lots of small oily fish.

There are some named fish meals with a more consistent composition such as salmon meal or herring meal available to manufacturers.

But most of the time these fish protein meals vary in their composition and it’s easier for pet food businesses to just use generic “fish meal”.

The purpose of including fish meal in dog food is to provide a high-quality source of protein and essential nutrients. It is highly digestible and contains all of the essential amino acids that dogs need.

In addition, fish meal is also a good source of omega-3 fatty acids which are known for their anti-inflammatory properties.

Fish Oil

This is the oil that gets extracted while processing whole fish or by-proucts such as cannery waste into a fish mail.

Fish oil is especially high in polyunsaturated omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

Fish Flavor

Most dogs love the taste of fish.

Fish hydrolysates such as enzymatic fish digest can be used as natural flavoring due to their strong umami taste^[9].

Hydrolyzing breaks down fats into fatty acids and proteins into peptides and amino acids. This results in a highly digestible and flavorful ingredient.

Hydrolyzed fish protein is also used in some hypoallergenic diets because they are less prone to cause allergic reactions.

Another fish ingredient is fish broth made from simmering seafood, whole fish or fish parts in water. It’s rich in moisture, protein and also provides lots of fish aroma.

Fish Species in Dog Food

Dog food manufacturers can choose from a large variety of fish. Some are super common (salmon or whitefish) while many others are quite rare and used in only a handful of products each.

Many of marine fish are exploited to the point of a decline in their populations and the fishing industry has a major impact on the environment. So feel free to ask dog food brands directly about how they source the fish ingredients in their products.

Overall, when choosing a fish-based dog food, look for one that uses high-quality and sustainably sourced ingredients:

Salmon

Salmon is a quality source of protein and is considered a very healthy food although there are variations in quality. It’s a fatty fish rich in omega-3 fatty acids and other nutrients.

Common varieties include Pacific or Atlantic salmon, sockeye salmon, and wild-caught or farm-raised fish.

Anchovies

Anchovies are small oily fish species.

They are used due to their high protein and healthy fat content. They provide essential nutrients like omega-3 fatty acids.

As a small and very flavorful ingredient, anchovies can add both nutrition and taste to a dog’s diet.

Arctic Char

Arctic Char (Salvelinus alpinus) is the most northern-living freshwater fish. In the wild, this cold-water fish is found in lakes, rivers, and coastal waters.

It is mostly produced in commercial fish farms in Canada. Arctic char resembles a salmon and is in fact closely related to both salmon and lake trout.

Alaska Pollock

Alaska pollock (Gadus chalcogrammus) is a marine fish native to the Bering Sea and related to the Atlantic cod.

Atlantic Pollock

Atlantic pollock (Pollachius pollachius and Pollachius virens) are marine fish native to the North Atlantic.

It’s a large whitefish, known to be low in mercury, and a natural source of omega-3 fatty acids and highly digestible protein.

Mackerel

Mackerel include a number of different species of oily fish.

They often swim in large schools near the surface and are intensively harvested by humans, some are overfished.

Mackerel is very rich in omega-3 fatty acids and provides quality protein and other essential nutrients. But it spoils quickly, so many dog foods opt to use more stable mackerel meal.

Herring

Herrings are a group of oily forage fish often found in large schools. They are intensively harvested and a staple food in many cultures, Europeans called them the “silver of the sea“.

Most commercially used species belong to the genus Clupea such as Atlantic herring (Clupea harengus) or the more overfished Pacific herring (Clupea pallasii).

Sardines

Sardines are yet another group of small marine oily fish. They are related to herring and are sometimes called pilchards.

They almost exclusively feed on zooplankton and are rich in EPA and DHA. Since forage fish are low in the food chain they are less likely to accumulate pollutants such as mercury.

Trout

Trouts are a group of fish closely related to salmon and char. They are usually restricted to freshwater while some like the steelhead trout spend some time at sea before returning to freshwater.

Many trout such as the rainbow trout are common food fish known to be tasty, tender, and flakey but somewhat bony.

Both wild and farm-raised rainbow trout can be a good source of polyunsaturated fatty acids while wild trout is lower in fat.

Cod

There are different species that are marketed as cod.

The two most common are the Atlantic cod (Gadus morhua) and the Pacific cod (Gadus macrocephalus).

Cod is a marine fish with dense, flaky, white flesh. It’s a type of ocean whitefish. Cod livers are used as a rich source of vitamins A, D and E, and omega-3 fatty acids (EPA and DHA).

Tuna

Found in all the world’s oceans, tuna are agile predatory fish that are highly sought after for their commercial value.

The predominant species harvested is skipjack tuna. Tuna is a great source of protein, as well as vitamins and minerals such as vitamin D, B¹², and selenium. It is also rich in omega-3 fatty acids.

Hake

Hake is a type of whitefish that is commonly found in the Atlantic and Pacific oceans. It is a member of the cod family and is known for its mild, delicate flavor and flaky texture.

Hake is a good source of protein, vitamins, and minerals, including vitamin B¹², phosphorus, and selenium. Additionally, hake is low in fat and calories.

Haddock

The haddock (Melanogrammus aeglefinus) is a marine fish native to the North Atlantic.

Commercial haddock fisheries are found on both sides of the ocean and haddock is a popular edible fish. So there are plenty of leftovers that can be used in dog foods.

Haddock is a very low-fat white-fleshed fish and a good source of protein, phosphorus, magnesium, vitamin B₆, and niacin.

Blue Whiting

Blue whiting (Micromesistius poutassou) measures about 30 cm and is mostly found in the northeast Atlantic Ocean.

It is often processed into fish meal and fish oil.

Unfortunately, this schooling fish is heavily commercially exploited by trawling and is at risk of overfishing.

Catfish

Catfish is a type of freshwater fish that is commonly found in rivers, lakes, and ponds throughout central North America.

It is an edible fish often raised in aquacultures and known for its mild, sweet flavor and tender, flaky texture. But farmed catfish contain higher proportions of omega-6 fatty acids compared to marine fish.

Bass

There are many species of perchlike marine or freshwater fish that qualify as bass with striped bass, sea bass, and white bass being the most common.

Bass is considered a low-calorie food and lower in omega-3 fatty acids compared to oily marine fish. But bass provides lots of digestible protein and other essential nutrients.

Acadian Redfish

Acadian redfish is an excellent ingredient for dog food. Its firm and flaky meat provides a lean protein source that is low in saturated fat.

Additionally, it is rich in essential nutrients like niacin, vitamins B₆ and B₁₂, sodium, calcium, protein, phosphorus, and selenium.

Rockfish

Rockfish is a term used for a variety of fish species, one commercially important one is the genus Sebastes.

These fish are also marketed as rockfish, ocean perch, sea perch, or redfish. They are high in protein and low in saturated fats.

In a BBC rating, rockfish was voted one of the most nutritious foods.

Capelin

Capelin (Mallotus villosus) are small fish found in the North Atlantic, North Pacific, and Arctic oceans.

They live in huge swarms and are a key food of the Atlantic cod. Unfortunately, some populations are threatened by overfishing.

Commercially, capelin is mainly used for fish meal and fish oil production. Its flesh resembles that of herring.

Capelin is a good source of vitamins D, A and B₁₂. They’re also rich in omega-3 fatty acids such as EPA and DHA.

White Trevally

The white trevally or striped jack is a tropical warm-water fish.

They have pink flash and are low in oil but still provide lots of omega-6 and omega-3 fatty acids. It’s a nutrient-dense quality ingredient.

Bream

This is actually a term used to describe a variety of fish species that share a narrow, deep body structure.

Bream can be a freshwater or marine fish and include black bream, gilt-head bream, and porgy.

Commercially fished species have firm, white flesh, and a mild flavor. However, some species of bream are at risk of being overfished.

Kahawai

Kahawai (Arripis trutta), also known as Australian salmon or salmon trout, is a marine fish from the South Pacific.

It is largely wild caught, but is considered a low-cost seafood as it is not very popular with consumers.

It is however, nutritious and contains a lot of omega-3 fatty acids, which makes it a good choice for dog food.

Halibut

A term used for several species of flatfish, most commonly North Pacific halibut (Hippoglossus stenolepis). Since halibuts are long-lived and mature slowly they have a hard time recovering from overfishing.

They are not oily fish, and mainly provide lean protein, B vitamins, and some minerals.

Silver Carp/Copi

The silver carp (Hypophthalmichthys molitrix) is a small freshwater fish from Asia.

Silver carp is widely produced in commercial aquaculture but escaped in some places or was introduced to control algae growth.

In North America, for example, it’s considered a highly invasive species that is extremely abundant in many Midwestern rivers.

The species was renamed silver copi or just copi in 2022. Mainly, to give it a clean slate and increase demand. That’s because consumers think of silver carp as a pest and not as food.

Monkfish

Monkfish are a group of anglerfish in the genus Lophius which are also called sea-devils. They are mostly caught by bottom trawling making their sustainability somewhat questionable.

Monkfish provide protein and are low in fat. They are white, meaty fish with a mild flavor and firm texture.

Monkfish is a good source of essential nutrients, such as vitamins B¹² and D, phosphorus, and selenium.

Sole and Flounder

These are various types of marine bottom-feeding fish flatfish.

Common species in the US are the summer flounder (Paralichthys dentatus) and the winter flounder (Pseudopleuronectes americanus), both native to the Western North Atlantic.

The common sole (Solea solea) on the other hand, is a fish found in the Eastern Atlantic Ocean and more common in Europe.

Hoki

Another name for these thin and tapered fish are blue hake or blue grenadier. Hoki (Macruronus novaezelandiae) is a very important commercial species marketed in New Zealand and Australia.

It’s a marine whitefish with flaky skin, a sweet taste, and lean meat. However, there is some conflicting information about the sustainability of commercial hoki trawling.