Does Your Cat Love Fish?

If your cat loves fish, he has lots of company! However, it’s really not a good idea to feed fish to your cat; and here’s why:

The primary fish used in cat food are salmon, tuna, and tilefish (ocean whitefish). Let’s look at each of these.

Salmon: The vast majority of salmon today comes from farm-raised fish. In this form of factory farming, millions of these unfortunate animals are kept in huge, overcrowded pens in polluted coastal waters. They’re fed antifungals and antibiotics to limit the spread of disease, and dyes to make their flesh salmon-colored (otherwise it would be gray). Common water pollutants, such as PCBs, pesticides, and other chemicals, are found in farmed salmon at ten times the amount found in wild fish. These contaminants will be present in any product made with farmed fish, including pet food.

It has recently been revealed that krill, tiny shrimp that are the natural diet of many whales and other marine animals, are being netted in vast hauls, and processed into food for these “franken-salmon,” for their protein as well as their red color. The issues with krill are explained below.

Tuna: It’s the fish that’s most “addictive” to cats. They love it so much that they may stage a hunger strike by refusing their regular food until they get it!

Tuna and other predatory fish are at the top of the food chain. This means that they may accumulate high levels of heavy metals (including mercury) as well as PCBs, pesticides, and other toxins, by eating smaller fish. The older the fish, the more contamination.

Tilefish: (listed on pet food labels as “ocean whitefish”) are among the worst contaminated, along with king mackerel, shark, and swordfish. These fish are so toxic that the FDA advises women of child-bearing age and children to avoid them entirely; and the FDA recommends only one serving of albacore tuna per week due to its high mercury levels.

The fish used in canned pet foods is typically whole fish, or leftovers from processing whole fish, deemed unsuitable for human consumption; this includes guts, feces, and bones, which are high in phosphorus—a problem for cats with kidney disease. On the other end of the urinary tract, many sensitive cats develop cystitis (bladder inflammation) and even urinary blockages if they eat any kind of fish at all. Fish and fish meal are both problematic.

A small amount of fish, such as wild caught sardines, used as a flavoring in a properly balanced, fresh meat-based diet, is not a problem. But fish should not be the main course for the cat’s diet.

But what about Omega 3 fatty acids? Aren’t fish and fish oils the best sources of these essential fats for our pets? Indeed, daily Omega- 3 supplementation from a marine source is extremely important for our cats as well as for us. Among many other benefits, Omega 3s fight inflammation, which affects our cats as much as it does us.

Krill is a popular non-fish source for Omega-3 oil. Krill are the major food source for many marine animals, including fish, whales, seals, and birds. Yes, there are a lot of krill in the sea, but the problem is that they are being harvested near critical feeding grounds of the animals that eat them. When even Whole Foods stops selling krill oil, as they did in 2010 due to concerns about sustainability, you know there’s a problem!

Cats do benefit greatly from an Omega-3 marine lipid supplement every day, but as we have seen, fish and krill oils are not the most environmentally friendly choices. Nor are they necessarily healthful. Many fish oils are processed by boiling the oil to separate it from heavy metals and toxins (distillation). Fish oil processing may also include the use of, alcohol, salts, solvents, and deodorizers to disguise the foul smell of the oil—a problem because fish decompose very quickly, turning the oil rancid before it can even be processed.

Additionally, as energy medicine practitioners, quantum physicians, and homeopaths know, the original energetic essence or “memory” of those heavy metals and pollutants, remains “imprinted” in the greasy substance that remains. The Omega 3s that survive, EPA and DHA, may be artificially concentrated in the process. It may be fair to say that the higher milligram values listed on fish oil labels are not necessarily better, as this is not the way they occur in their raw, natural state.

We need an alternative source of marine lipids for all these reasons, as well as the cautions mentioned for the eating of these fish.

Research suggests that the New Zealand, greenlip mussel (perna canaliculus) is our best choice for Omega 3’s. These greenlip mussels (GLM) are raised 100% sustainably. They are very low on the food chain; and have no fins, feet, or faces. GLM are bi-valve mollusks known to be a rich source of 33 fatty acids; 18 of them Omega 3s. GLM contain a unique array of Omega 3s. One of the most fascinating is ETA (eicosatetraenoic acid). ETA, which is not found in any other foods to any measurable degree, has extremely powerful ant-inflammatory properties.

The best scenario is to source a greenlip mussel oil that is organic, cold-extracted, and certified to be free of mercury and other toxins and pollutants. Ideally, choose a GLM marine lipid product which also contains antioxidants with high ORAC values (a measure of antioxidant power), such as cold-pressed, organic grape seed husk extract and/or kiwifruit seed oil—these will naturally deactivate free radicals, as well as serve as natural preservatives for the GLM oil.

While it doesn’t affect quality, a common complaint about fish oil capsules is their size. They are enormous! GLM oil comes in tiny capsules that are perfect for cats, who will often eat them right from your hand; or they can be punctured and the contents mixed with wet food.

Sources for quality Omega 3 greenlip mussel oil supplements are available online, and are proving to be the most beneficial and ecologically sound alternative to fish and krill oil.


Nancy P.
Nancy P.4 years ago


Elisabeth T.
Elisabeth T.5 years ago

Good information, thanks for sharing...

Lika S.
Lika S.5 years ago

Oh, and the canned is once a week treat, unless it's a holiday, then they get extra.

Lika S.
Lika S.5 years ago

I can't afford to feed my cats real fish. They get Purina dry cat food, and fancy feast canned cat food.

Diane L.
Diane L.5 years ago

Yup, Helen, seen that! Problem is, cats can lose so much body weight in a day, it's scarey! I don't want mine gettng too thin, so I just don't get the stuff that I think she'll want but is bad FOR her. My vet said once that while it's best to feed the BEST stuff one can get, at some points in time, it's most important that they just EAT, period. I had an old cat that I rescued (he was almost 18 when I found him) and at the last stages before he passed (almost 21), he wouldn't eat, so I'd pour human tunafish JUICE on his food to entice him. I knew it wasn't good for him, BUT he needed to eat SOMETHING, ya' know?

Of my 5 cats, the two outside cats will eat anything, and one of the inside cats will, but she will upCHUCK the cheap stuff. One is very fussy and she's the one who was having seizures, was put on a raw diet, but now eats "selected" cans, only certain flavors. No seizures now in almost 3 months and no "meds".

Helen K.
Helen K.5 years ago

Yes, I agree with the hunger-strike-'till-I-get-my-TUNA. But then we went through a very poor phase when we had very little money and their volume of food was cut back (as was mine). It did us a lot of good and my cats will now eat anything. (And I lost 40lbs! the upside of the recession)

Diane L.
Diane L.5 years ago

Here's a link about krill (just one of dozens)............ for salmon, again, I live in Puget Sound, and over the years, caught more than a "few", and never saw a grey one yet. Sockeye, Coho and Steelhead are all different in flesh color. Copper River (from Alaska) makes them ALL "pale" in comparison, though, and at $19/lb, none of my 5 cats will ever get even a morsal of that. I can't afford it for myself!

Diane L.
Diane L.5 years ago

Basically, a well-written article. However, there are some assumptions made as well as unsustatiated rumors and falsehoods. For example, not all salmon is "red" or "orange" naturally, but grey? Hardly. It depends on the species, the age of the fish and where it's been feeding. Atlantic Salmon are NOT as brightly colored as Pacific Salmon, especially when they return to spawn, and Alaska Salmon are the reddest of all. Factory Farmed fish are probably duller in color because first of all, they never live long enough to mature and BECOME red/orange, which is from becoming older and with more fat. The more FAT, the redder the flesh.

Krill is one of the most abundant species on the planet, so it's false to assume that by using them as food for animals, or their oil (which is EXTREMELY HEALTHY for humans) it is contributing to the demise of the species.

I would agree about tuna, and also that fish as the main source of "meat" in a cat's diet is not good. While obligate carnivores, cats do better on a varied MEAT diet, and the closest to nature and raw, the better.

Parvez Z.
Parvez Zuberi5 years ago

Thanks for the info

Claire C.
Claire Chambers5 years ago

My cat eats almost no human food at all -very little, although I let her see and smell what I'm eating. He just likes dry cat food only no treats and no canned food.