Why Do Our Cat Like Fish?

Why Do Our Cat Like Fish

Cat’s common to see a rival relationship between a cat and a pet fish on animated TV shows and films. The four-legged character usually tries to catch the swimmer with the intent of snacking on them. Most of the time, the cat will become frustrated and walk away; if only reality were a cartoon universe! Your fur baby has all the faculties needed to prey on your goldfish and make him his dinner. So, why do cats like fish?

Cat lovers will attest that the sight of a canned tuna is enough to send a cat into hysteria. We went on a mission to investigate everything cats and fish. We were able to come up with several theories that seek to explain why your kitty would go down on his knees for a meal of tuna. Is it nature or nurture? The following information will help you deduce this.

Below, find the reasons behind your cat’s love for fish. We will also explain why too much fish is bad for your cat and the consequences of letting him overindulge. Did you know that some cats are allergic to fish? We will explain how this is diagnosed and treated. With this information at your fingertips, you can be sure that your cat has a ‘safe’ relationship with fish.

The Reasons Cats Like to Eat Fish

Domestication has molded cats into people-friendly creatures—making them less of predators and more of cool pets. Although your cat may seem all timid and docile, he is a certified killing machine. If he was in the wild, his diet would consist entirely of meat.

The reasons behind cats’ predominantly meat-based diet and specifically fish for this matter can be summed up as both instinctual and opportunistic in nature.

They Need Fish in Their Diet

They Need Fish in Their Diet

Cats are obligate carnivores. This means that their genetic make-up is wired to consider meat as their primary food source. Their bodies have evolved both physiologically and metabolically to require high protein diets. They must eat the tissue of other animals in order to survive and thrive.

A feline’s body needs arginine and taurine. These are amino acids which are needed to biosynthesize or break down proteins in the body. Unlike humans, a cat’s metabolism cannot down-regulate protein requirement. In the absence of these essential proteins, their bodies will result in ‘digesting’ their own muscles.

Also, while most mammals synthesize the amino acids from seeds and dairy products, cats cannot and require them to be pre-formed.

Fish has these amino acids in large quantities which can be the reason cats go for the delicacy.

Cats also need pre-formed vitamin A. Their digestive enzymes cannot break down carotenoids which is the plant-based source of vitamin A. This is despite the fact that plants such as carrots and spinach, which are high in Vitamin A, make up some of the ingredients in cat food. Fish and meat have pre-formed vitamin A in the form of retinoid.

Finally, while humans and plants can synthesis Vitamin D from sunlight in varying degrees, cats can’t. They need it to be pre-formed for their bodies to benefit from it. Their only choice is to get it from animal tissue or as a supplement. They also need pre-formed omega 3 acids which fish is known to have a high content of.

Fish was Used for Domestication

Fish was Used for Domestication

This might sound farfetched, but once you consider the history of feline domestication, the picture becomes clearer. One of the theories on the domestication of cats holds that the practice started in Ancient Egypt. It goes that cats were drawn to humans since they could feed on their leftover foods.

Ancient Egyptian cities were situated along rivers and other water bodies. Fishing was a major economic activity at the time. It makes sense that cats would be drawn to man’s homes where there was an abundance of food.

With fish being the main menu, our furry friends were slowly introduced to it. They found it good for their tummies and decided to stick around for more.

This is supposed to have taken place about 4,000 years ago. As man and cat grew close, raw fish was used to keep the felines inside homesteads. The arrangement worked since cats were of service to man; cats could rid the homes of mice and other rodents who wreaked havoc on grain storages.

Cats are opportunistic feeders. 

Cats are known to utilize and eat whatever food source is commonly available in their surroundings and this includes the food that people give them such as fish bones and fish leftovers as well as garbage that they see on streets and garbage bins. 

Cats are attracted to the strong smell of fish.

Cats are attracted to the strong smell of fish.

While cats only have 470 taste buds and have a limited ability to detect various tastes and flavors,  their sense of smell is extraordinary because it’s 9 to 11 times stronger than a human’s.  This may well explain why, aside from various other odors and scents, cats are drawn to fish because of its strong smell and aroma. 

Do some cats hate fish?

Yes, there have been pet parents who attest that their cats don’t eat fish. It depends on each cat’s preference for food. It may also be because some cats were not introduced yet to a fish-based diet. Some pet parents also claim that their cats do not eat salmon or tuna while some others prefer pork or chicken meat instead of fish. Some cats are also allergic to fish and will avoid eating fish altogether. Cats that are allergic to fish may suffer the following symptoms: inflamed skin, vomiting, diarrhea, hair loss. and scratching, wheezing, and sneezing or coughing. 

Is Fish Dangerous for Cats?

It’s evident that cats not only love fish but will actively hunt for it if need be. The cat food you buy from your local pet store will usually have fish as one of the major ingredients. Moreover, your furry baby is probably hooked on the stuff and will go nuts whenever fish is in the menu.

Why Do Our Cat Like Fish?strong smell of fish.

Yet the big question remains: can fish be dangerous for your cat?

The simple answer is that the consumption of fish can be harmful to you and your feline friend if not eaten in moderation. Some specific types of fish can be very harmful to the extent of causing infections to your four-legged friend.

Is there something that can be done to ensure that your kitty enjoys the delicacy and remains safe? Certainly; here is what you can do:

Urinary Tract Infection

It’s recommended that you go for pet food from reputable manufactures. There have been recorded cases of cats developing kidney problems after eating canned tuna.

Some canned fish meant for cats is made from decaying and leftovers crumbs from the seafood industry. This unregulated food usually has high levels of magnesium and phosphorous. These two metallic compounds, if consumed in high quantities, can cause urinary tract disorders in cats.

Feline Hyperthyroidism

Feline hyperthyroidism has also been linked to diets that are heavy on fish. Senior cats are more prone to the illness, and a fish-based diet may worsen the situation considerably.

Fish Allergy

Fish-based food is ranked among the top causes of allergic reactions in cats. It contains high levels of histamine which is responsible for most allergies.

An allergic reaction occurs when the body fights against the fish protein. This happens as a result of the body’s defense system misjudging fish as an invasive substance.

Intolerance of the food is usually accompanied by several symptoms. The most common sign is gastrointestinal upsets. You will hear gurgling sounds from your cat’s stomach.

Inflammation of the skin may also occur, especially among felines who are allergic but insist on feeding on fish-based foods. Papules and lesions will appear on the skin, making it very itchy. Your cat will start scratching his coat, which may lead to hair loss.

These symptoms are similar to those caused by pests or bacterial infestation. It’s therefore paramount that you take your cat to the vet the moment you notice any of the tell-tale signs of allergies.

The vet will need information on the type of food that your cat is taking. With that, it will be easy to determine the ingredient that is causing the allergy. There are some ingredients which when added commercially to a canned fish meal may cause allergies. Knowing the exact mishmash of nutrients or additives present in the cat food will make it easier to diagnose allergies.

A common approach to allergy treatment is introducing your cat to an elimination diet. This involves feeding him food devoid of fish or the suspected allergy-causing portion of his diet. His progress is observed as the elimination continues.

While residual symptoms are common during the treatment period, allergic reactions clear quickly once the allergen has been isolated. Vets will prescribe antibiotics to combat the resulting skin inflammations to avoid secondary infections during the recovery period.

Be Careful of Mercury Poisoning

One of the major concerns when it comes to fish is mercury poisoning. Predator fish such as salmon and tuna have high levels of this highly poisonous metal. The same goes for others like the swordfish, sharks, and mackerels.

The ocean is full of plastic and other manmade waste. These materials are toxic and they move up the food chain from the small fish that consume them to the predatory fish and lastly into your pet.

Food with a high percentage of fish can be toxic especially to women and children. People are advised to tread carefully when it comes to eating fish so it makes sense that you should mind how much fish your kitty consumes.

What types of fish should you feed your cat?

What types of fish should you feed your cat?

Cats can eat any type of fish if they’re not allergic to it. The most recommended types of fish for consumption are tuna and salmon because they’re good sources of Omega-3 and fatty acids. However,  these types of fish have high mercury content. Cod, flounder, and halibut are smaller types of fish with less mercury and they’re presumed to be safer for cats to eat.  Take extra precautions when giving canned fish because of the high sodium content. 

These are the health benefits of nutrients from fish for cats:

  • protein – helps cats to stay healthy, builds tissues, regulates pH balance, and provides energy
  • taurine – an amino acid that controls heart rhythm, vision, reproduction, and digestion
  • Omega 3 fatty acids –  keeps the coat glossy and shiny, reduces inflammatory conditions like asthma, inflammatory bowel disease, arthritis, skin disease, and lessens the risk of cancer 

How often should your cat eat fish?

Cat experts recommend that you should only give fish to your cats at least two or three times a week.  This is because while fish contains taurine and protein which are important nutrients for cats, it also contains thiaminase that breaks up thiamine or Vitamin B1 which is an essential part of a cat’s nutritional requirements. If cats are thiamine-deficient, their nervous system becomes prone to fatal damage.   Fish also has mercury which can be toxic for cats when taken in large quantities as it may lead to urinary tract infection (UTI) and hyperthyroidism. 

Why do cats stare at fish in an aquarium? Does it mean they like to eat it?

Why Do Our Cat Like Fish?

Most cats do instinctively watch and stare at fish inside an aquarium or fish tank because their interest are piqued with the fish swimming about in the water.  But it doesn’t always mean that they’re thinking of eating the fish in the tank. Most of the time, watching the fish swimming in circles is pure entertainment for cats and they’re staring at it because it got their attention. However, given the chance and pure luck, some cats will attempt and succeed at catching the fish which eventually becomes a quick snack! 


Cats like fish because they learned to co-evolve with humans who hunt and eat fish, thus, cats have also come to like and eat fish. However, not all cats like fish because each cat has its own preferences while some others are allergic to it.  While fish contains nutrients that are essential for cats like taurine, Omega 3 and thiamine, it should be given in moderation only as over-consumption of fish could lead to health issues like hyperthyroidism and urinary tract infection. 

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