Oily Fish for Dogs: Which Ones and How Much
Written by Lucy Fitzgerald, Founder, WYLDR. Reviewed by Katie McCaul, RNutr, The Pet Diet.
Key takeaways
- Sardines, mackerel, salmon, herring, sprats and anchovies are the oily fish most often fed to dogs.
- Oily fish are the richest whole-food sources of the long-chain omega-3 fats EPA and DHA.
- Tinned sardines in spring water, drained and with no added salt, are the simplest practical option.
- Small oily fish are generally preferred over large predatory fish, which accumulate more mercury.
- Serve them as a topper, not a meal, and keep them plain: no salt, oil, brine, tomato sauce or seasoning.
- Alongside the benefits of omega-3, oily fish also bring heavy metals, salt and fat-soluble vitamins, all of which can be overdone if fed in high quantity.
The short answer: The oily fish suited to dogs are sardines, mackerel, salmon, herring, sprats and anchovies. They are the richest whole-food source of EPA and DHA. Serve them cooked or tinned in spring water, drained and plain, as a small topper rather than a meal. Remove the bones from any fish you cook yourself.
"Oily fish" is a slightly unhelpful label, because it groups together fish that suit dogs very well and fish that suit them less. This guide sorts out which is which, covers tinned versus fresh, and answers the practical questions: the bones, the salt, the sauce and how much is actually sensible.
What counts as an oily fish
In short: Oily fish store fat throughout the flesh rather than concentrating it in the liver. That fat is where the omega-3 sits.
The oily fish list is: salmon, sardines, mackerel, herring, sprats, anchovies, trout, pilchards and, at the larger end, tuna. White fish such as cod, haddock, pollock and whiting are not oily fish. They are perfectly good lean protein for a dog, but they are not a meaningful source of omega-3.
The fat is the point. Oily fish carry eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the two long-chain omega-3 fats that come up most often in canine nutrition research. Our guide to omega-3 for dogs explains why these two specifically, and why plant omega-3 is not the same thing.
Worth knowing before anyone sells you on it: FEDIAF's 2025 Nutritional Guidelines set a minimum EPA plus DHA level for puppies but state that current information is insufficient to recommend a level for adult dogs. Oily fish are a good thing to understand and a reasonable thing to feed. They are not a nutritional obligation with an agreed number behind them, because dogs can survive without them. They simply do better with them, because of the anti-inflammatory properties of omega-3.
Which oily fish suit dogs best
In short: Small oily fish are the practical choice. Sardines, sprats, anchovies, mackerel and herring are short-lived and low in the food chain. Salmon works well too. Large tuna is the one to be more careful with.
These are easy to source tinned, or dried, as well as cooked.
Sardines. The most practical option for most owners. Small, cheap, widely available tinned in spring water, and rich in omega-3.
Sprats and anchovies. Small, whole, and often sold dried as single-ingredient treats, which makes them easy to portion. Check for added salt on dried products, which is common.
Mackerel. Rich, fatty and strongly flavoured, which fussy dogs often like. Fresh mackerel needs the pin bones removing. Tinned in spring water is easier.
Herring. Same broad picture as mackerel. Less commonly sold in dog-friendly tinned form in the UK.
Salmon. Covered in full in our guide to can dogs eat salmon. Cooked, boneless and plain.
Trout. Fine cooked, boneless and plain. Lower in omega-3 than salmon or mackerel.
Tuna. The one to go carefully with. Tuna is a large, long-lived predatory fish, and larger predatory species accumulate more mercury than small short-lived fish, which is why human food safety guidance advises limiting certain tuna. We have not seen dog-specific guidance putting a figure on this, so we are not going to invent one. The sensible position is that tuna is an occasional item rather than a regular one, and that a sardine does the same nutritional job with less to think about.
Tinned, fresh, frozen or dried
In short: Tinned in spring water, drained, is the easiest. Fresh needs cooking and deboning. Dried is convenient but check the salt.
Tinned. Look for "in spring water" with no added salt. Drain it. Avoid tinned in brine, in oil, in tomato sauce or in any flavoured sauce, all of which add salt, fat or ingredients dogs do not need.
Fresh. Cook it through, plain, with no oil, butter or seasoning and nothing from the onion and garlic family. Remove the bones. Let it cool before serving.
Frozen. Fine, treated as fresh once defrosted. Defrost in the fridge rather than on the counter.
Dried. Dried sprats, whitebait and fish skins are sold as single-ingredient treats and are genuinely convenient. Read the label: some are salted, and salt is the thing to avoid.
Raw. We would not. Raw fish can carry parasites and bacteria that cooking removes, and there is no nutritional benefit worth the risk. If you feed raw and want fish in the rotation, that is a sourcing-and-freezing conversation with a nutritionist or your vet rather than something to improvise.
The bones question
In short: Remove the bones from any fish you prepare yourself. Cooked bones from fresh fish are the ones to avoid.
Fish bones need care. Pin bones in fresh mackerel and herring are firm, and cooking makes bones more brittle rather than softer, so anything you cook at home should be deboned before it goes in the bowl.
The rule that keeps you out of trouble: if you cooked it yourself, debone it. If your dog is a gulper rather than a chewer, or is a smaller breed, take extra care and ask your vet what they are comfortable with.
How much oily fish, and how often
In short: As a topper, not a meal. Small amounts, a couple of times a week, is a common and sensible pattern.
How much to feed will also depend on your current diet. Oily fish is helpful for a home-cooked or raw diet to help complete the recipe, but we need to be more mindful for those dogs already receiving these nutrients from a balanced complete processed food.
Oily fish is calorie-dense and fatty. Extras of any kind should stay a small share of daily intake, with the bulk coming from properly balanced food. A portion of tinned sardine over dinner two or three times a week is a reasonable rhythm for most dogs, scaled down considerably for a small dog.
We have not given a grams-per-kilo figure. The numbers circulating online come mostly from people selling fish, and portioning for your specific dog, at its weight and on its current diet, is a question for your vet or a qualified nutritionist. It is not possible to say how much your dog needs without knowing its current diet and lifestyle.
Introduce it gradually. A sudden jump in dietary fat is one of the more reliable ways to give a dog loose stools.
Which dogs should skip it
In short: Dogs with a diagnosed fish allergy, dogs on an elimination diet, dogs with pancreatitis or fat sensitivity, and any dog whose vet has said otherwise.
Fish allergy in dogs exists, though it is less common than chicken or beef. Dogs on a veterinary elimination diet should not have anything added, including fish, because it invalidates the trial. And because oily fish is high in fat, dogs with pancreatitis or a history of it need veterinary advice first. Our guide to sensitive stomach dogs covers the wider picture on reactive dogs.
Where WYLDR fits
WYLDR's Every Dog Every Day contains salmon oil, which is the concentrated marine route to the same EPA and DHA found in a sardine. Whole fish and a daily oil do slightly different jobs: the fish brings protein and variety, the oil brings the fats without the bones or the smell. That is a description of composition rather than a promise about results.
One bite. Dosed. For the whole dog.
Join the waitlistFrequently asked questions
Can dogs eat sardines?
Yes. Tinned sardines in spring water, drained and with no added salt, are one of the simplest ways to add omega-3 to a dog's bowl. Serve them as a topper rather than a meal, a couple of times a week for most dogs.
Can dogs eat mackerel?
Yes, cooked plain or tinned in spring water and drained. Fresh mackerel needs its pin bones removed. Mackerel is rich and fatty, so portions should be modest.
Can dogs eat tinned fish in oil or brine?
No. Fish tinned in brine carries too much salt, and fish tinned in oil adds unnecessary fat. Tinned in spring water, drained, is the version to buy. Avoid anything in tomato or flavoured sauce.
Can dogs eat tuna?
Occasionally, plain and tinned in spring water. Tuna is a large, long-lived predatory fish, and larger predatory species accumulate more mercury than small short-lived fish. Smaller oily fish such as sardines provide the same omega-3 with less to consider.
Is white fish as good as oily fish for dogs?
White fish such as cod and haddock are good lean protein but are not a meaningful source of omega-3. If omega-3 is the reason you are feeding fish, an oily fish is the one to choose.
How often can a dog eat oily fish?
A small portion a couple of times a week is a common and sensible pattern for most dogs, scaled to size. Oily fish is fatty and calorie-dense, so it should stay within the small share of the diet reserved for extras. Portioning for your specific dog is a question for your vet.
Can dogs eat raw fish?
It is best avoided. Raw fish can carry parasites and bacteria that cooking removes, and there is no nutritional benefit that justifies the risk.