With caution — cats and tuna in olive oil
Tuna in olive oil is not toxic to cats, but it is a worse choice than tuna in springwater for regular feeding. The tuna itself is fine; the olive oil adds unnecessary saturated and monounsaturated fat, disrupts the omega fatty acid balance, and increases the caloric density without any benefit. If springwater tuna is available, use that. If olive oil tuna is all you have for a one-off treat, drain it very thoroughly first.
🏆 Pet Care Community Safety Score™ — Tuna in Olive Oil for Cats
"I have to be direct: there is no scenario where tuna in olive oil is better for a cat than tuna in springwater. The olive oil adds fat without adding the omega-3s that make oily fish beneficial — olive oil is monounsaturated fat (oleic acid), not EPA or DHA. What you get is a higher-calorie, higher-fat version of tuna with no nutritional upside. The other issue with tuna generally — not the oil — is addiction. Cats that eat tuna regularly often refuse all other foods. I've had clients with cats that would not eat any commercially formulated cat food because tuna had become the only acceptable option. That is a nutritional emergency in slow motion."
The straight answer
Tuna in olive oil will not poison your cat. The tuna is fine; olive oil is not toxic. What you have with oil-packed tuna compared to springwater tuna is higher calories, more fat (particularly monounsaturated fat that provides no cat-appropriate benefit), and a disrupted fatty acid balance that works against the reason you'd want to feed oily fish in the first place. If you have the option, springwater tuna is always the better choice. If all you have is olive oil tuna, drain it well and serve occasionally.
The omega-3 problem with olive oil packing
The reason tuna and other oily fish are sometimes recommended for cats is the long-chain omega-3 fatty acids — EPA and DHA — which support coat condition, joint health, and kidney function. Olive oil is primarily oleic acid, a monounsaturated fat, with minimal omega-3 content. When tuna is packed in olive oil, two things happen:
- Some omega-3s from the fish leach into the oil, which you drain away — reducing the omega-3 content of the tuna you actually serve
- The olive oil that remains in and on the drained fish adds oleic acid, which competes with omega-3 for absorption and metabolism in a way that marginally reduces the effective omega-3 benefit
This is not a dramatic effect — drained tuna in olive oil still contains meaningful omega-3. But it is consistently inferior to springwater packing.
The tuna addiction problem — more relevant than the oil question
Tuna is one of the most palatable foods for cats. Some cats, particularly those on dry food that has low palatability, latch onto tuna as the preferred food and gradually stop accepting anything else. Unlike the chicken-breast preference (which is common), tuna addiction is nutritionally more concerning because:
- Tuna is low in taurine compared to meat or organ protein
- Tuna is high in unsaturated fat — feeding large amounts regularly depletes vitamin E and can cause steatitis
- Mercury accumulation in tuna (a large, longer-lived species) is a real consideration with daily feeding
- A cat that only eats tuna is not on a nutritionally complete diet
A cat that has been eating tuna in olive oil daily for months and refuses other food needs a dietary intervention, not more tuna. Gradual transition — mixing decreasing amounts of tuna with increasing amounts of a complete cat food — over 2–3 weeks usually works.
Springwater vs. oil-packed tuna: a direct comparison
| Factor | Tuna in springwater | Tuna in olive oil |
|---|---|---|
| Sodium | ~200–280mg/100g | ~300–400mg/100g |
| Calories per 100g | ~116 | ~185 |
| Fat | ~0.5g | ~8–10g (drained) |
| Omega-3 retention | Higher | Lower (leaches into oil) |
| Cat-appropriate choice | Better | Acceptable if well-drained |
🚨 My Cat Ate Tuna in Olive Oil — What Now?
Tuna in olive oil is not a toxicity risk. Contact your vet if your cat shows signs of steatitis (painful skin nodules, reluctance to be touched) after prolonged high-fish feeding.
Signs that warrant a vet call:
- Loose stools
- vomiting from fat content if too much oil is ingested. Signs of steatitis with very frequent fatty fish feeding (painful fat deposits under the skin). With chronic tuna-only feeding: signs of thiamine or vitamin E deficiency
If your cat ate a large amount or is showing the signs above: Don't wait — call immediately.
📞 Animal Poisons Helpline: 1300 869 738Available 24/7 across Australia. Have your cat's weight, breed and approximate quantity consumed ready when you call.
Frequently Asked Questions
2–3 times per week maximum for any tuna, in small amounts. Daily tuna feeding risks mercury accumulation, taurine insufficiency (tuna is lower in taurine than meat protein), and the addiction problem. Sardines in springwater are a better regular fish choice because they are lower in mercury, higher in omega-3, and less addictive to cats than tuna.
For the full comparison of fish options for cats, see our guide to canned sardines for cats and our cat food safety hub.
📚 Sources & Further Reading
- Munday JS, et al. Steatitis in cats — association with excessive dietary unsaturated fat. N Z Vet J 2001.
- ASPCA Animal Poison Control — Fish for Pets. https://www.aspca.org
- Cornell Feline Health Center — Feeding Your Cat. https://www.vet.cornell.edu
- Australian Veterinary Association — Feline Nutrition. https://www.ava.com.au
