Many owners wonder whether they can offer their cat raw fish as part of their diet, inspired by the feline's carnivorous nature or by the BARF feeding approach. The answer is yes, but with some essential precautions: raw fish can be an excellent source of protein for your cat, provided you manage the parasitic and nutritional risks correctly. According to veterinary studies, around 15–20% of cats fed raw diets receive fish regularly, yet only 40% of owners apply adequate safety protocols such as preventive freezing.

The real risks of raw fish for cats

Before adding raw fish to your cat's bowl, you need to be aware of three key risks documented in the veterinary literature and in the FEDIAF guidelines on feline nutrition.

Parasites: Anisakis and other nematodes

Anisakis is the most common parasitic hazard for cats. This nematode infests more than 70% of raw marine fish (cod, mackerel, anchovies, wild salmon). The larvae survive in the cat's gastrointestinal tract, causing:

  • Acute vomiting within 6–12 hours of ingestion
  • Diarrhoea, possibly with blood
  • Abdominal pain and loss of appetite
  • Allergic reactions in severe cases

A 2019 study published in Veterinary Parasitology found Anisakis larvae in 12% of Italian domestic cats regularly fed untreated raw fish. Other parasites include Diphyllobothrium latum (fish tapeworm) and Opisthorchis felineus, which is particularly prevalent in freshwater fish.

Thiaminase: the enemy of vitamin B1

Some raw fish species contain thiaminase, an enzyme that destroys thiamine (vitamin B1), which is essential for the feline nervous system. A B1 deficiency can cause:

  • Neurological symptoms: ataxia, seizures, tremors
  • Progressive loss of appetite and weight loss
  • Mydriasis (dilated pupils) and temporary blindness
  • In severe cases, coma and death within 2–4 weeks

Species with high thiaminase content include carp, herring, cod, sardines and raw molluscs. As little as 2–3 weeks of feeding exclusively on these fish can cause a clinical deficiency. The minimum thiamine requirement for cats is 5–6 mg/kg of dry matter (AAFCO guidelines).

Heavy metals and environmental contaminants

Fish, especially large predatory species, accumulate mercury, PCBs and dioxins. Tuna, swordfish and king mackerel contain mercury concentrations 3–5 times higher than sardines or anchovies. Chronic exposure can cause kidney and neurological damage in cats, animals that are already predisposed to chronic kidney disease.

How to make raw fish safe: the freezing protocol

The most effective method for eliminating parasites is preventive freezing, recommended by EC Regulation 853/2004 for human consumption and equally applicable to cats.

Blast-freezing temperatures and times

To kill Anisakis larvae and other parasites, fish must be frozen according to the following parameters:

  1. -20°C for 7 days (domestic freezer, 3–4 star rating)
  2. -35°C for 15 hours (professional blast chiller)
  3. -15°C for 96 hours (minimum acceptable, less reliable)

Domestic freezing at -20°C for one week is the ideal compromise: accessible, affordable (approximately €0.15–0.20 of electricity per kg of fish) and scientifically validated. Remember to freeze the fish when it is very fresh — within 24 hours of purchase — in portions of 50–100 g to make thawing easier.

Correct thawing procedure

Thawing should take place slowly in the refrigerator (4–6 hours per 100 g) or under cold running water. Never thaw at room temperature or in the microwave, as both methods alter the protein structure and create conditions for bacterial proliferation. Thawed fish should be used within 24 hours.

Freezing does not destroy thiaminase

Important: cold temperatures do not destroy the thiaminase enzyme. To inactivate it, cooking is required (above 80°C for 5 minutes). If you want to give your cat raw fish that is high in thiaminase, limit the frequency to 1–2 times per week and supplement with vitamin B1 sources (liver, heart, specific supplements).

Which fish can you give your cat raw

Not all fish are equal. Here is a practical guide based on safety, nutritional value and availability.

Safe and recommended fish (with freezing)

  • Sardines and anchovies: low mercury, rich in omega-3 fatty acids (EPA/DHA), calcium from the bones. Cost: €6–10/kg fresh
  • Mackerel: excellent lipid profile, but watch out for thiaminase. Maximum once a week
  • Cod and hake: lean and easily digestible, ideal for overweight cats. Low thiaminase
  • Salmon: farmed only (lower parasite risk), very rich in omega-3. Cost: €12–18/kg
  • Trout: farmed, a good quality-to-price option (€8–12/kg)

Fish to avoid or limit

Not recommended for frequent use:

  • Tuna: high mercury content; risk of steatitis (inflammation of subcutaneous fat) if given in excess
  • Swordfish: very high mercury content; never give raw
  • Carp and freshwater catfish: very high thiaminase content; risk of specific parasites
  • Raw molluscs: possible accumulation of algal biotoxins; bacterial risk

Whole fish or fillets only?

In the wild, cats eat whole prey. Offering small whole sardines (10–15 cm) provides calcium from the bones, taurine from the organs and encourages chewing. For older cats or those with dental problems, finely chopped fillets are safer. Always remove large, hard bones.

Frequency and quantity: how much raw fish to give

Raw fish should not form the basis of a feline diet, but rather serve as an occasional protein supplement or as part of a balanced BARF diet.

Frequency guidelines

For an adult cat weighing 4–5 kg on a BARF diet:

  1. 1–2 times per week: raw fish as a complete meal (50–70 g), alternated with meat (chicken, rabbit, beef)
  2. 3–4 times per week: small amounts (20–30 g) as a topper on commercial food
  3. Never exclusively: a fish-only diet leads to imbalances (excess phosphorus, calcium deficiency, vitamin B1 deficit)

Nutritional balance

A meal of raw fish alone is lacking in:

  • Calcium: add raw meaty bones (chicken wings) or calcium carbonate (800–1,000 mg per 100 g of fish)
  • Taurine: fish contains less taurine than meat. Supplement with 250–500 mg/day if fish makes up more than 30% of the diet
  • Vitamin E: needed to metabolise omega-3 fatty acids. Supplement with 10–20 IU per fatty fish meal

WSAVA guidelines recommend consulting a veterinary nutritionist for home-prepared raw diets, especially for cats with conditions such as diabetes or kidney disease.

Signs of overfeeding

Too much raw fish can cause:

  • Persistent diarrhoea (excess omega-3 fatty acids)
  • Frequent vomiting (protein intolerance)
  • Hair loss and dermatitis (vitamin E deficiency, excess iodine)
  • Neurological symptoms (vitamin B1 deficiency from thiaminase)

BARF brands and products with fish for cats

If you prefer convenience, several Italian and European companies offer raw fish that has already been blast-frozen and nutritionally balanced for cats.

Reliable commercial products

On the Italian market you can find:

  • Renske Fresh Meat: balanced raw salmon with vegetables and supplements. Cost: €4–5/400 g
  • Naturina Elite: BARF range with sardines and mackerel, frozen. Cost: €3.50–4.50/250 g
  • Barf-Barf: white fish mix (cod, plaice) with bones and organs. Cost: €6–8/500 g
  • Nutriment (imported from the UK): wild salmon with green tripe. Cost: €5–7/500 g

These products are already blast-frozen to -20°C, balanced in accordance with FEDIAF standards and ready to serve. Always check the label: it should state "complete and balanced" or "complementary food" (in the latter case, supplementation is required).

DIY: preparing home-made portions

To save money (average cost €2–3/portion vs €4–5 for commercial products):

  1. Buy 2–3 kg of fresh sardines at a fish market
  2. Clean them, portion into bags of 60–80 g
  3. Freeze at -20°C for 7 days
  4. Before serving, add: ¼ teaspoon of calcium carbonate, 50 mg powdered taurine, 10 IU vitamin E

Keep frozen portions for up to 3 months. Label each bag with the freezing date.

Raw fish vs cooked fish: which is better?

Both options have documented advantages and disadvantages.

Advantages of raw fish

  • Preserves natural digestive enzymes and heat-sensitive omega-3 fatty acids
  • Greater palatability for many cats
  • Texture closer to natural prey
  • Keeps taurine intact (which is sensitive to heat)

Advantages of cooked fish

  • Eliminates thiaminase and parasites without the need for freezing
  • Reduces bacterial risk (Salmonella, Listeria)
  • Safer for immunocompromised or elderly cats
  • Easier to digest for cats with IBD

The ideal cooking method is steaming (5–7 minutes) or boiling (8–10 minutes), without any salt or seasoning. Cooking destroys approximately 20–30% of omega-3 fatty acids and 10–15% of taurine, but makes the fish 100% safe.

Which should you choose for your cat?

Choose raw fish if:

  • Your cat is an adult in good health
  • You can guarantee freezing at -20°C for 7 days
  • You follow a structured BARF diet
  • You want to maximise omega-3 and taurine intake

Opt for cooked fish if:

  • Your cat is a kitten, elderly or immunocompromised
  • You do not have a reliable freezer
  • Your cat has gastrointestinal problems
  • You want simplicity and complete peace of mind

Frequently asked questions

Can I give my cat sushi or sashimi?

Yes, but with care. Sushi is safe for cats only if the fish has been blast-frozen to -20°C (most restaurants are legally required to do this). Avoid sushi with sauces (soy sauce, wasabi, mayonnaise), seasoned rice, avocado or other ingredients that are toxic to cats. Plain sashimi — salmon or tuna — is the better option, in small amounts (10–15 g) as an occasional treat. The high cost (€15–25/100 g) makes it impractical as a regular food.

Can raw fish cause allergies in cats?

Yes, fish is among the top 5 feline allergens. Around 5–10% of cats develop a hypersensitivity to fish, with symptoms such as itching, dermatitis, vomiting or chronic diarrhoea. If you notice any of these signs after introducing raw fish, stop immediately and consult your vet. Allergies are more common with tuna and salmon than with white fish.

How much does it cost to feed a cat raw fish?

A 4 kg cat eating 50–60 g of raw fish twice a week will cost around €15–25 per month for the fish alone (sardines/mackerel at €8–10/kg). Adding supplements (calcium, taurine, vitamin E) brings the total to approximately €20–30/month. Commercial BARF diets cost €60–100/month. This is more affordable than premium dry food (€40–60/month), but requires more effort.

Is raw fish suitable for kittens and senior cats?

For kittens under 6 months of age, it is best to avoid raw fish: their immature immune systems make them vulnerable to parasites and bacteria. Opt for cooked fish or balanced commercial food instead. For senior cats (over 10 years), raw fish is fine if the cat is healthy, but consider cooking it if they have kidney, liver or immune system issues. Always consult your vet before changing the diet in these age groups.

Offering your cat raw fish can enrich their diet with high-quality protein and omega-3 fatty acids, but it requires knowledge and responsibility. Preventive freezing at -20°C for 7 days is the golden rule for eliminating parasites such as Anisakis, while rotating between different fish species and supplementing with calcium and vitamins prevents nutritional imbalances. If you are considering a transition to BARF feeding or simply want to add variety to your cat's diet, raw fish can be an excellent choice — always under the guidance of a veterinary nutritionist to ensure the long-term wellbeing of your feline companion.