Is raw tuna safe for ferrets?

Regularly feeding raw fish carries a real risk because of an enzyme called thiaminase, which can break down vitamin B1 over time. An occasional small amount is unlikely to cause a problem, but cooked, plain tuna is the safer choice if you want to offer it at all.

Can tuna replace part of a ferret's normal diet?

No. A complete ferret food is formulated around their specific high-protein, high-fat needs, and tuna alone does not provide that balance. Treat any tuna as an occasional extra on top of their proper diet, never as a substitute for part of it.

What tinned tuna is safe for ferrets?

If you offer any at all, choose tuna in spring water with nothing added, and drain it thoroughly, rather than tuna in brine or oil, both of which add unnecessary salt or fat. A small amount, rarely, is plenty.

My ferret had loose stools after eating tuna — what should I do?

A single episode of mild loose stools after a new food often settles on its own within a day. If it continues, your ferret seems unwell, or they stop eating, contact your vet rather than waiting to see, since ferrets can deteriorate quickly if they go off food.

Can ferrets eat tuna?

Ferrets can eat a small amount of plain, cooked tuna now and then without it doing any harm, but it should never become a regular part of their diet. Ferrets are obligate carnivores with specific nutritional needs that a proper ferret food is built to meet, and tuna on its own does not come close to covering them.

Why occasional is the right word here

Ferrets need a diet very high in animal protein and fat, and low in fibre and carbohydrate, which is quite different from what a cat or dog needs, let alone a human diet. Tuna offers protein but nothing like the full nutritional profile a ferret needs day to day, so relying on it, even occasionally in large amounts, risks displacing the balanced food that should make up almost everything they eat.

Raw fish, tuna included, also carries a genuine concern: an enzyme called thiaminase that can break down vitamin B1 if raw fish is fed regularly. A occasional small amount is unlikely to cause a problem, but it is a real reason not to make raw tuna a habit, and cooked tuna avoids the enzyme issue entirely.

How to offer it safely, if you want to

If you do want to give your ferret a taste of tuna, choose a small piece of plain, cooked fish with no salt, oil, seasoning or sauce, and keep the portion genuinely small — a token taste rather than a meal. Tinned tuna in brine or oil is not a good choice, since the added salt and fat are both worth avoiding.

Offer it rarely rather than as a regular treat, and watch how your ferret's stools look afterwards, since any sudden change in diet, however small, can cause temporary digestive upset in a ferret's fast, short digestive system.

What should make up most of a ferret's diet

A complete food formulated specifically for ferrets should make up the bulk of what they eat, since it is built around their high protein, high fat, low carbohydrate needs in a way that occasional treats, tuna included, simply cannot replicate. Cat food is sometimes used as a stopgap by owners who cannot get ferret-specific food, but it is not an ideal long-term substitute, since it is formulated for a different animal.

Fresh water should always be available, and any treats, tuna or otherwise, should stay a small fraction of what a ferret eats in a day, the same principle that applies to treat feeding in most pets.

Why ferrets are different from cats and dogs here

It is worth being specific about why ferrets get less flexibility with foods like tuna than a dog often does. Ferrets have a very short, fast digestive tract designed to process meat efficiently, and they gain relatively little benefit from anything that is not close to their natural high-protein, high-fat carnivorous diet — unlike a dog, which can tolerate a broader range of foods without much issue.

That short gut also means anything unfamiliar moves through quickly, which is part of why a sudden dietary change, even a small one, is more likely to show up as loose stools in a ferret than it might in a cat or dog of a similar size. Keeping new foods genuinely occasional and modest in amount respects that difference rather than treating every small pet's tolerance as the same.

Common questions

Is raw tuna safe for ferrets?: Regularly feeding raw fish carries a real risk because of an enzyme called thiaminase, which can break down vitamin B1 over time. An occasional small amount is unlikely to cause a problem, but cooked, plain tuna is the safer choice if you want to offer it at all.
Can tuna replace part of a ferret's normal diet?: No. A complete ferret food is formulated around their specific high-protein, high-fat needs, and tuna alone does not provide that balance. Treat any tuna as an occasional extra on top of their proper diet, never as a substitute for part of it.
What tinned tuna is safe for ferrets?: If you offer any at all, choose tuna in spring water with nothing added, and drain it thoroughly, rather than tuna in brine or oil, both of which add unnecessary salt or fat. A small amount, rarely, is plenty.
My ferret had loose stools after eating tuna — what should I do?: A single episode of mild loose stools after a new food often settles on its own within a day. If it continues, your ferret seems unwell, or they stop eating, contact your vet rather than waiting to see, since ferrets can deteriorate quickly if they go off food.

Sources

Written against guidance published by UK veterinary and welfare organisations. Always confirm specifics with your own vet.

Written by Matt Garnett, who runs Giddy Pets and is a lifelong pet owner — not a vet. This is general information, not veterinary advice, and it cannot replace an examination by the vet who knows your animal. How we write these guides.