It must be said that when we think of associating certain foods and our pets, cats and cats love eating fish are high on that list of association although the same cannot be said for our associating with fish and a lion.

However, it is important for us to know that it is not a question of if they don’t like or don’t want to eat fish but to know that eating fish is not good for them and can lead to a large percentage of food allergies too.  A small amount of tinned tuna can be considered periodically but must not form part of their regular diet.  Because we love our cat so much, we understand they too need certain vitamins and minerals not just to survive but equally as important to thrive too!

I have met quite a few people who have told me that their cats are not allowed to eat food containing fish and this has sparked my interest to find out more about it. 

Cats owners will know if their cat likes or dislikes fish!  Most cats go crazy for a tuna or sardine treat.  A small amount of fish added to their food now and then can be considered but must be avoided as a daily treat as it is not good for their well-being!  For humans, it would be like eating a chocolate filled diet instead of a well-balanced diet containing vitamins and minerals.

Eating too much fish, raw fish especially will deprive their body of essential vitamins and minerals that can lead to serious health problems.  The most common deficiency is thiamine deficiency; this is a shortage of vitamin B1.


Thiamine is one of the many types of vitamin B known as B1. It works with other B vitamins to improve the efficiency of metabolism energy.

Thiamine is an essential nutrient that all tissues of the body need to function properly. Thiamine was the first B vitamin that scientists discovered. Therefore, its name carries the number 1. Like the other B vitamins, thiamine is water-soluble and helps the body turn food into energy. You can find it in foods, individual supplements and multivitamins.  The body needs thiamine to make adenosine triphosphate (ATP). This is a molecule that transports energy within cells.

All high energy functioning organs like the liver, heart and kidneys in our cat's body require thiamine to function. Thiamine deficiency is the most common cause of vascular problems, pertaining to vessels and nerve damage. Thiamine is essential for the production of energy in the central nervous system.

Thiamine is very sensitive to heat so not only is raw fish a problem but also highly over-processed food that we tend to feed our pets nowadays.


  • Lethargy: Unable to process energy.

  • Drooling: Indication of early neurological symptoms.

  • Vomiting: Unable to process and break down food efficiently.

  • Anorexia: Can not process food.

  • Seizures: Develops from the brain’s lack of appropriate energy source.

 As the saying goes, prevention is better than cure!  This can be done by buying a healthy balanced food for your cat, preferably food from your nearest pet or vet shop and not a supermarket.  Do not feed your cat raw homemade meals that include raw fish containing none of the necessary vitamins they need.

Although thiamine deficiency can be life-threatening it is easy to treat and you will need to take your fur baby to the vet. Make sure you have all the information necessary as your vet will need to know what symptoms your cat is experiencing to help them put a treatment plan in place.

Treatment will usually include giving your cat an injection of thiamine under the skin as thiamine is absorbed extremely quickly into the body. With your help, the vet will establish what could have caused the deficiency and will identify the changes you need to put into place, need it be dietary or certain food elimination.