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Tuna
Tuna
Plain, cooked tuna is not toxic to cats and is often used as a flavour enhancer in cat food. However, regular feeding of tuna — especially raw tuna — creates significant health risks: thiamine deficiency, mercury accumulation, and nutritional imbalance. Tuna should be an occasional treat, not a dietary staple.
Important Notes
Thiaminase risk: raw tuna contains thiaminase, which destroys thiamine (B1); regular raw tuna feeding causes neurological damage — weakness, head tilt, seizures
Mercury risk: tuna is high in mercury; chronic exposure causes neurological damage, kidney damage, and immune suppression
Nutritional imbalance: tuna alone lacks several essential nutrients for cats (calcium, vitamins) and is high in unsaturated fats that deplete vitamin E
Canned tuna in water (plain, no salt): safe as an occasional treat; avoid tuna in oil or with any added salt
A small piece of plain cooked tuna occasionally is fine; daily feeding is not recommended
Potentially Toxic Parts
Raw form
Entire food
Juice
Possible Symptoms Reported in Cats
Neurological Dysfunction (Methylmercury Poisoning)
Neurological · Chronic (accumulates over time with regular feeding).
Neurological Dysfunction (Thiamine Deficiency) (Note
Neurological · Chronic / Delayed (typically develops within 2 to 4 weeks of a raw fish-heavy diet).
Steatitis (Yellow Fat Disease)
Dermal · Chronic (develops over weeks to months of a diet heavy in tuna).
Gastrointestinal Upset and Salt Toxicosis (Note
Gastrointestinal · Acute (within hours to a few days of ingestion).
While a tiny bite of plain, cooked tuna is generally safe as a rare treat, feeding a cat a diet heavy in tuna
Metabolic
Disclaimer: This summary was compiled from multiple sources and is for informational use only. It is not a diagnosis or treatment plan. Toxicity can vary based on the substance, amount, plant part, and individual cat. If you think your cat may have been exposed to a toxic substance, contact a veterinarian right away.