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Fish in the cat's diet



Fish offers the cat  an important supply of Omega3, essential fatty acids.

In fish, Omega3s are in the form of EPA and DHA, which are immediately bioavailable for the body


It is advisable to feed fish in a percentage equal to 5% of the ration.

With fish not containing thiaminase, it can reach 10% (more on this later).

The fish can be fed whole, with bones, head, skin and viscera.

It is absolutely essential to freeze before administration, in order to kill the parasite Anisakis (a nematode. In short, a worm!) Possibly present.

It is not uncommon for fish to have this parasite, so freeze! _Cc781905-5cde-3194-bb3b-136bad5cf58d_

It is necessary to freeze for at least 96 hours.

For fish purchased already frozen (for example the classic cod fillets) obviously it is considered that the procedure has already been extensively carried out!



What does 5% mean in practice?


It means 5% of the diet, whether calculated daily, weekly, monthly or otherwise.

Practical example:

A cat (about 6 kg)   that eats 160 grams of total food per day, weekly this   will eat 1120 grams of food (160 x 7). 5% of 1120 is 56. So this cat will eat 56 grams of fish per week.

They may also be offered 110 gr of fish every 2 weeks for example.


Of course we are not goldsmiths and the percentages are general indications.

The important thing is to understand that you shouldn't go too far. Surely we must not exceed 10% of the total.



Thiaminase is an enzyme that breaks down thiamine. Thiamine is vitamin B1. Thiaminase essentially inactivates vitamin B1.

Therefore, the administration of foods containing thiaminase can lead to a deficiency of vitamin B1, if the recommended quantity is exceeded.

Many freshwater and saltwater fish contain thiaminase, however not all.

However, it is not easy to draw up a detailed list, since there are hundreds and hundreds of fish species in existence… and not all of us are experts in fish and the fish also change in common name from area to area.

Here are some lists found:


1) Taken from "Mink breeding and diseases" published by the Foundation for zooprophylactic and zootechnical initiatives


Fish containing thiamiasis:

- Anchovies


- Bleak


- Alose



-European bass

-Carps and Cyprinids






-Persico trout


- White freshwater fish

-Blue saltwater fish (rafts, sardines, mullets)



-Red rudds


- Mackerel


2) Taken from

Thiaminase and its role in predatory pet fish (and other piscivores) nutrition


Fishes NOT containing  tiaminasi (I report some of them. Others seem hardly present in Italy, such as North American sunfish for example !!):


- Zander (Sander lucioperca)

- Lake char (Salvelinus namaycush)  

- Rainbow trout (Oncorhynchus mykiss)

Pike (Esox lucius)

- Atlantic salmon (Salmo salar)

--Silver salmon (Oncorhynchus kisutch)  

- Salmon trout (Salmo trutta)

-Anguilla (Anguilla anguilla)

-Platess (Pleuronectes platessa)

- Cod (Gadus morhua)

-Ricciola (Seriola dumerilii)

-Spinarolo (Squalus acanthias)

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