Can Cats Eat Sardines? Water, Bones, and Brine

Name: Can Cats Eat Sardines? Water, Bones, and Brine
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

Can cats eat sardines? Yes, in most cases a small amount of plain sardine is safe for a healthy adult cat. The catch is in the can. Sardines packed in water with no added salt are a reasonable occasional treat, while sardines in brine or heavy oil bring far more salt and fat than a cat needs. This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Plain sardines packed in water, with no added salt or seasoning, are safe as an occasional treat for most healthy adult cats.
Sardines in brine are too salty. Skip them, and never pour the brine into your cat's bowl.
Sardines in oil add a lot of fat and calories. Drain them and rinse if you use them at all, or choose water-packed cans.
Bones in canned sardines are soft and usually fine, but large or firm pieces can be a choking risk. Mash them well or remove them.
Treats should stay a small part of the diet. Ask your veterinarian how much fits your cat's weight and health.

The Verdict: Safe or Unsafe?

Plain sardines are safe for most cats. A sardine is a small oily fish, and cats are obligate carnivores, meaning they are built to eat animal tissue. A bite or two of plain fish fits that pattern.

The problems come from what is packed around the fish. Brine is salt water, and a cat's sodium needs are low. Oil packs fat and calories. Some cans add garlic, onion powder, or other seasonings, and those can be toxic to cats. So the fish itself is not the issue. The can is.

If you want to share sardines, read the label first. Look for sardines, water, and nothing else. If salt, oil, garlic, onion, or spices appear, put the can back.

What Is in a Sardine?

Sardines are a protein-rich fish with fat, including omega-3 fatty acids. Fish oil is a common supplement in feline nutrition, and research in healthy adult cats shows that fish oil supplementation lowers plasma triacylglycerols and shifts the plasma lipid profile, including increases in specific triacylglycerols containing eicosapentaenoic acid and docosahexaenoic acid [1]. Those are the long-chain omega-3 fats many owners are hoping to add when they feed fish.

That does not mean a can of sardines is a supplement. The dose of fish oil used in that study was measured in grams per kilogram of body weight per day and was given as a controlled supplement, not as table food [1]. Your veterinarian calculates any supplement dose from your cat's weight and health. A sardine treat is food, not medicine.

Sardines also carry calories and fat. For a cat watching its weight, a few bites can matter more than you expect. For a cat with kidney disease, heart disease, or a sensitive stomach, even plain fish may not be the right choice.

Can Cats Eat Sardines in Water?

Yes. Water-packed sardines are the best option if you want to feed sardines. The packing liquid is water, so you avoid the added salt of brine and most of the added fat of oil.

Even here, check the label. Some water-packed cans still list salt. Some list "sardines, water, salt," which is not the same as plain. Choose cans where the ingredient list is short.

Serve a small piece at room temperature. You can mash it with a fork so your cat does not have to tear off a big chunk. If your cat has never had fish, start with a tiny taste and watch for vomiting, diarrhea, or itching over the next day. Some cats have food sensitivities, and fish is a common trigger.

If you are comparing fish options, our guide on can cats eat tuna or sardines walks through how the two fish differ.

Can Cats Eat Sardines With Bones?

Usually yes, if the bones are the soft, crumbly kind found in canned sardines. Those bones are cooked until they soften, and many cats chew and swallow them without trouble. They also add a little calcium.

The risk is size and firmness. A large, firm bone piece can lodge in the mouth or throat. Cats do not chew as thoroughly as people do, and a cat that gulps a treat may swallow a piece whole. Mash the sardine with a fork and break up any firm bones before you offer it. If a bone feels hard between your fingers, remove it.

Never feed raw or undercooked fish bones. Raw bones splinter and can injure the mouth, throat, or gut. Canned sardine bones are the only kind to consider, and even then, mashing is the safer habit.

Watch your cat while it eats. If it paws at its mouth, drools, swallows repeatedly, or gags, stop and call your veterinarian.

Can Cats Eat Sardines in Brine?

No. Brine is salt water, and it is the main reason to avoid this form. A cat's body is not built to handle a salty snack, and too much sodium can cause vomiting, diarrhea, lethargy, tremors, and in severe cases neurologic signs.

The same caution applies to the liquid in the can. Do not let your cat drink brine, and do not pour it over food to make it more appealing. If you have already opened a brine-packed can, drain it and rinse the fish well under running water. Even rinsed, it is a second-best choice. Water-packed is better.

If your cat licked brine or ate a brine-packed sardine, offer fresh water and call your veterinarian or a pet poison hotline for guidance. The ASPCA Animal Poison Control Center is available at (888) 426-4435, and the Pet Poison Helpline is available at (855) 764-7661. A fee may apply.

Our article on can cats eat tuna and brine covers the same salt problem in a different can.

Can Cats Eat Sardines Packed in Oil?

It is not ideal. Oil-packed sardines carry extra fat and calories, and rich, greasy food is a common cause of vomiting and diarrhea in cats. A single oily bite may be fine for a healthy cat, but repeated oily treats can add up.

If oil-packed is all you have, drain the oil, rinse the fish in water, and offer only a small piece. Do not use the oil as a topper. Some oils, such as those flavored with garlic or herbs, are unsafe for cats.

There is a bigger concern with fatty meals in cats. A very fatty meal can trigger gastrointestinal upset, and cats with a history of pancreatitis should avoid high-fat treats entirely. If your cat has had pancreatitis, ask your veterinarian before feeding any fish.

Can Kittens Eat Sardines?

Kittens should not get sardines as a regular treat. A kitten's diet needs to be complete and balanced for growth, and table food crowds out the nutrients it needs. Occasional tiny tastes are unlikely to harm a healthy kitten, but they are not necessary.

Kittens also have small mouths and small stomachs. A piece that seems tiny to you can be a choking risk or cause diarrhea. If you want to give your kitten a treat, use a commercial treat made for kittens, or ask your veterinarian what is appropriate.

For adult cats, the same portion logic applies. A treat should be a small fraction of daily calories. Your veterinarian can tell you what that means for your cat's weight and body condition.

Form-by-Form Guide

Form	Safe?	Notes
Plain sardines in water, no salt	Yes, as an occasional treat	Best choice. Mash and serve a small piece.
Sardines in water with added salt	Limit or avoid	Check the label. Salt adds sodium your cat does not need.
Sardines in brine	No	Too much salt. Do not let your cat drink the liquid.
Sardines in oil	Not ideal	Extra fat and calories. Drain and rinse if used at all.
Sardines with garlic, onion, or seasoning	No	Garlic and onion can be toxic to cats.
Canned sardines with soft bones	Usually yes	Mash well and remove any firm pieces.
Raw sardines or raw bones	No	Raw bones splinter. Raw fish is not a safe treat.
Sardines in tomato sauce or mustard sauce	No	Added salt, sugar, and seasonings.

Risks to Know Before You Share

Salt. Brine and salted water are the biggest hazards. Too much sodium can cause vomiting, diarrhea, lethargy, tremors, and neurologic signs. Cats with heart or kidney disease are at higher risk.

Fat. Oil-packed fish and large portions can trigger stomach upset and diarrhea. Cats with pancreatitis or a history of GI problems should avoid fatty treats.

Choking and blockages. Firm bones, large chunks, and whole fish can lodge in the mouth or throat. Mash the fish and watch your cat eat.

Toxins in the food chain. Fish-based pet foods can carry higher levels of some metals than poultry-based foods. In one comparison of commercial dry cat foods, cadmium concentrations were significantly higher in fish- and red meat-based diets than in poultry-based diets [2]. All measured metal concentrations stayed below established regulatory limits in that study, but the finding is a reminder that fish is not a free pass [2]. Wet cat foods have also shown measurable mercury in some samples, along with signs of oxidation and biogenic amines that indicate microbial activity or lower-quality raw materials [3]. These findings support keeping fish as an occasional treat, not a staple.

Additives. Garlic, onion, and onion powder can damage a cat's red blood cells. Some cans also include sugar, mustard, or tomato sauce. Read every label.

Contaminants in commercial pet food. A survey of chicken-based cat kibbles found residues including antibiotics, PFAS, toxic metals, and BPA in some samples, which shows that contaminant exposure in pet food is a real concern across protein sources [4]. Choosing a plain, simple product and keeping treats small lowers the odds of a problem.

How to Offer Sardines Safely

Read the label. The ingredient list should say sardines and water. Nothing else.
Drain the liquid. Do not save it for your cat.
Rinse if the fish was packed in brine or oil.
Mash a small piece with a fork and remove any firm bones.
Serve at room temperature, not cold from the fridge.
Offer a small amount the first time and watch for vomiting, diarrhea, or itching.
Keep sardines occasional. They are a treat, not a meal.

Never feed sardines as a replacement for a complete and balanced cat food. If you want to add omega-3s for a health reason, ask your veterinarian about a fish oil product made for cats. Our article on can cats eat sardines? omega 3 benefits and sodium limits goes deeper on that trade-off.

What to Do If Your Cat Ate Too Much

If your cat ate a large amount of sardines, or ate a brine-packed or oil-packed can, act based on what you see.

Ate brine or a salty can: Offer fresh water and call your veterinarian or a pet poison hotline. Watch for vomiting, diarrhea, wobbliness, tremors, or unusual behavior.
Ate a lot of oily fish: Expect possible stomach upset. Withhold other treats and call your veterinarian if vomiting or diarrhea starts.
Ate garlic or onion seasoned fish: Call a pet poison hotline or your veterinarian right away. Garlic and onion toxicity can develop over hours to days.
Choking, gagging, or pawing at the mouth: This is an emergency. Go to a veterinary clinic now.
Ate a firm bone and seems uncomfortable: Call your veterinarian the same day.

Do not try to make your cat vomit unless a veterinarian tells you to.

Safer Alternatives

If you want to give your cat a fish treat, plain water-packed sardines in a small portion are one option. Other choices include:

Commercial cat treats made for your cat's life stage.
A small piece of plain cooked chicken or turkey with no seasoning.
A spoonful of plain, unsalted bone broth for hydration. Our article on can cats eat bone broth? joint health and hydration explains how to choose one.
A veterinary omega-3 supplement if your veterinarian recommends one.

If your cat needs more water in its diet, talk to your veterinarian about wet food. Wet cat foods are high in moisture, and that can help with hydration [3]. Senior cats in particular benefit from attention to water intake and protein quality, though official nutrition guidelines for older cats are still limited [5].

Limitations and When to Contact a Veterinarian

This article covers general guidance only. Every cat is different, and individual cases need a veterinarian who knows your cat's history, weight, and health conditions.

Call your veterinarian the same day if your cat ate brine, oil-packed fish, or a garlic or onion seasoned product, or if it has vomiting, diarrhea, or a poor appetite after a treat.

Go to an emergency clinic now if your cat is choking, gagging, having trouble breathing, trembling, wobbly, collapsing, or having a seizure.

Schedule a routine visit if your cat has repeated stomach upset after fish, if you are unsure whether a treat fits its diet, or if you want to add omega-3s for a health reason. Your veterinarian can calculate what is appropriate for your cat's weight and health.

Frequently Asked Questions

Can I feed my cat sardines every day?

No. Sardines should be an occasional treat, not a daily food. A daily fish treat can crowd out balanced nutrition, add extra fat and sodium, and increase exposure to metals that can concentrate in fish.

Are canned sardines with bones safe for cats?

Usually yes, if the bones are soft and you mash them well. Firm or large bone pieces can choke a cat, so break them up or remove them before serving.

Can cats drink the water from a can of sardines?

No. Even water-packed cans can contain added salt, and the liquid is not a substitute for fresh water. Pour it out and give your cat clean water instead.

What if my cat ate sardines in brine?

Offer fresh water and call your veterinarian or a pet poison hotline. Watch for vomiting, diarrhea, lethargy, tremors, or unusual behavior, and seek care if any of those appear.

Is fish bad for cats with kidney disease?

It can be. Cats with kidney disease often need controlled protein, phosphorus, and sodium, and fish may not fit that plan. Ask your veterinarian before feeding any fish to a cat with kidney disease.

References

Impact of a Dietary Fish Oil Supplementation on the Plasma Lipidome of Healthy Adult Cats. Metabolites, 2026.
Comparison of As, Cd, Cu, Fe, and Pb levels in dry cat foods containing different protein sources (poultry, fish, red meat) and in cats consuming these diets. Veterinary research communications, 2026.
Physicochemical Quality and Chemical Safety of Commercial Wet Cat Food: Composition, Oxidation, Biogenic Amines, and Trace Elements. Journal of animal physiology and animal nutrition, 2026.
Multiple contaminant detection in commercially available chicken-based cat kibbles in Italy. Frontiers in veterinary science, 2026.
EXPRESS: What Goes in the Bowl? Evidence-Based Nutrition for Ageing Domestic Cats. Journal of feline medicine and surgery, 2026.