Salmon, tuna, and ocean whitefish are some of the most common ingredients in commercial cat food, but are they safe for your cat to eat? Given the fantastic marketing that seafood receives, you wouldn’t be alone in assuming it’s a nutritious food source for your cat. And it’s partly true; fish is a great source of omega 3 and 6 (and it doesn’t hurt that most cats go wild for it).
But many vets are voicing their concerns about feeding fish to cats, and they’re right to be worried. Feeding your cat fish raises some significant health concerns, including kidney problems and the risk of thiamine deficiency.
Is it safe for my cat or kitten to eat fish?
Yes – it’s safe for your cat to eat fish in small amounts and as part of a balanced diet. But is it actually good for them? Well, cats are a lot like humans in this way – everything in moderation. Fish can be a wonderful, nutritious treat.
Health problems tend to arise when you feed your cat fish regularly, or as a primary source of protein in their diet. Commercial, fish-based cat foods (and even some home-cooked diets) just don’t have enough of a variety of meat in them to be nutritionally complete. This is why, if you look in the fine print on the tin, it usually says ‘as part of a balanced diet’ or ‘supplementary to a balanced diet.
So what happens if you feed your cat a fish-based food?
Health risks associated with fish-based cat food
FLUTD and Kidney Disease
Urinary crystals are a major health concern for cats. They can quickly cause a urethral blockage and become fatal. They’re expensive to treat, and once your cat has had them once, they’re more likely to get them again.
Magnesium and phosphorus are the two main culprits that lead to the formation of these crystals – and fish are full of them. If your cat has developed these before, your vet most likely recommended special urinary dry food to prevent the issue from coming back.
The idea behind these foods is that they have lower levels of magnesium and phosphorus. Some also have high salt content to encourage your cat to drink more. But personally, it makes more sense to me to prevent crystals forming in the first place by feeding a balanced raw diet that is naturally lower in magnesium and phosphate.
Is Fish Bad for Male Cats?
A fish-heavy diet is unhealthy for male cats because it promotes the development of urinary crystals. These crystals cause blockages in your cat’s urethra, which can become fatal in less than 2-3 hours.
Hyperthyroidism
In 2007, the US Environmental Protection Agency detected a link between fish-based cat food diets and hyperthyroidism. Upon testing the cats’ blood, researchers found that cats who ate canned fish were exposed to 5 times the amount of toxins such as polybrominated diphenyl ethers (PBDEs) than cats eating non-fish diets.
Cats that eat canned food containing whitefish, salmon and other seafood are exposed to PBDE levels up to 12 times higher than cats that eat dry food, and five times more than cats that eat poultry or beef canned foods, the study said. The chemicals build up in oceans and other water bodies and magnify in food chains.
Los Angeles Times,16 August 2007 reporting on the US Environmental Protection Agency study.
These chemicals are widely used in the fish industry, and they negatively affect your cat’s endocrine and neurological systems. They also impact thyroid hormone production, leading to hyperthyroidism.
Thiamine deficiency
Fish contains high levels of an enzyme called thiaminase, which destroys thiamin. This can lead to a deficiency that causes neurological issues and seizures in cats and is fatal if left untreated.
Health benefits of fish
Despite its drawbacks, it’s hard to deny that fish has some nutritional benefits. It contains high levels of omega 3 and 6, which are essential to your cat’s diet. Without these, your cat can’t effectively absorb fat-soluble vitamins. These fatty acids also provide energy, and help your cat’s vision, brain development, and circulatory system health. They also give a boost to their coat and skin.
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Because fish isn’t a healthy part of your cat’s everyday diet, I prefer to add a fish oil supplement to my cat’s raw food. It’s a good way to get all the benefits of omega 3 and 6, without the high levels of magnesium and phosphorus that fish contains. Plus, they think it’s a really nice treat.
But don’t cats eat fish in the wild?
Would a hungry stray cat steal some fish out of your pond for a quick meal? Sure. But from an ancestral standpoint, cats evolved from the desert. So, no, they wouldn’t naturally eat fish. They would have primarily eaten small mammals like rats, mice, rabbits, and birds.
Should I feed my cat raw or cooked fish?
Fish is one of the few types of meat your cat shouldn’t eat raw. Raw fish can be contaminated with lots of different bacteria, including salmonella and E. coli. It also contains thiaminase, which can only be removed by cooking the fish.
For these reasons, we recommend only feeding your cat bits of boneless, cooked fish meat as a treat. This will also help to avoid you having to clean up any messy stomach mishaps afterward.
Can my cat eat fish bones?
Fish bones (raw or cooked) should be avoided. When raw, they can expose your cat to the same bacterial illnesses as raw fish. When cooked, they can splinter and cause potentially fatal internal damage.
Can cats eat raw salmon and sushi as a treat?
If your cat is anything like mine, they will line up to steal your sushi on takeaway night and bat it out of your hands just as you’re trying to take a bite. However, sushi (and the raw fish within it) is not a good snack for your cat. Although a small amount of fish is okay, the other ingredients in sushi may not be. Plus, it’s best to stick with cooked (and boneless) fish rather than raw salmon, since it can cause your cat some significant stomach upsets.
What’s the best meat protein to feed my cat?
There isn’t one single meat that’s best to feed your cat. Cats are healthiest when they are fed a balanced, raw diet with a lot of variety. We feed our cats a blend of boneless meat and offal, including turkey, kangaroo, beef, heart, liver and kidneys.
Although fish is a good treat, it’s not healthy to feed it to your cat as a regular part of their diet. Instead, we recommend a balanced raw diet.
