cat dreaming of fish

Guest post by Celeste Yarnall

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.


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.


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. The FDA recommends only one serving of albacore tuna per week due to its high mercury levels.

Tilefish (listed on pet food labels as “ocean whitefish”)

are among the worst contaminated fish, 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.

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.

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.

Alternative sources of Omega-3 fatty acids

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.

Celeste Yarnall, Ph.D was an author, lecturer and holistic practitioner and author of four books, including The Complete Guide to Holistic Cat Care, co-authored by Jean Hofve, DVM. 

This article was previously published on and was republished with the author’s permission.

Photo: dreamstime

29 Comments on Does Your Cat Love Fish?

  1. Hello Ingrid,
    I emailed Wellness about their fish used in their canned cat food, and here is what they answered. Given that they monitor and screen for heavy metals, does this make it OK to feed Wellness?

    Thank you!

    ” Thank you for taking the time to write to us about our Wellness® Wet Cat Food.

    Our salmon is wild caught 96% of the time. The majority of it is caught off the North Pacific coast and a small amount is caught off the North Atlantic coast. On occasion, about 4% of the time, the demand is greater than the supply. On these occasions we would use salmon from US farms. All of other fish used in our recipes is wild caught 100% of the time of the Atlantic coast.

    We regularly monitor and screen for heavy metals (Arsenic, Cadmium, Mercury, and lead) in all of our finished products containing fish. Mercury in fish is regulated and no fish with a level of mercury exceeding 1 mg/kg can be allowed to go into the food chain in the USA. All our finished products consistently test lower than 1mg/kg.

    Thanks again for contacting us. ”

    Consumer Affairs Representative

  2. Hi Ingrid, I just started feeding my cats the TC Gourmet Carnivore, Bonito Tuna which says it has mussels, squid & shrimp. How do I know what kind of mussels are used & is shrimp,squid or Tuna good for them? Also I have one cat who has chronic crystal issues so I wouldn’t feed him the fish. But there aren’t many brands that have urinary tract foods with a variety of flavors. Could you recommend a few? Thank you ~ Dotts

    • The only way to find out for sure what’s in those treats would be to call the company, Dottsie. I don’t recommend any fish or seafood products except as an occasional treat. The most important thing for cats with urinary tract issues is added moisture. These so-called urinary tract foods are primarily a marketing gimmick. You can find a wealth of information about this topic on Dr. Pierson’s site:

  3. Hi Ingrid, thanks for the useful article. It sounds like mussels have many nutrients essential for cats, and are one of the more ethically-sourced foods they can eat. I just wondered if it’s ok to give cats the meat of whole steamed mussels? I found a home made recipe online for cat treats using steamed mussels blended with some boiled veg and then baked into little patties, so was thinking of trying this. TIA!

    • It sounds like your kitties are in for a treat 🙂 I don’t see anything wrong with these mussel “cakes” as an occasional meal.

  4. I found a brand that I want to try out but it has salmon oil in it somewhere in the middle of the ingredient list. Is salmon oil safe to give my cats? One of my cats has recurring UTIs and I want to switch them to canned food

  5. I was wondering if Organic flaxseed oil for Omega 3’s would be o.k. for our two cats since I am going to be switching them to a homemade diet, the type you have suggested. But being a plant based omega 3 is it bad for them? Also where can I get Taurine supplement for them? Thank you for all you do!

    • While flax seed oil is a good source of omega 3 and actually contains higher levels of alpha-linolenic acid (ALA) than fish oil, as well as omega-6 fatty acids, cats (as well as dogs and some people) cannot efficiently convert ALA to the more active non-inflammatory omega-3 fatty acids (EPA and DHA), so fish oil is a better choice for cats. If you feed a commercially prepared diet, you shouldn’t have to supplement with taurine. For a homemade diet, I recommend this supplement:

  6. This is such helpful information. Are there any concerns with non-farm raised salmon? My 15 1/2 year old cat has kidney disease, and has recently become a very picky eater – he has been losing weight and often will only lick his wet food, rather than eating it. I’ve tried lots of different varieties and flavors of the various high quality brands and have yet to find one that he will consistently eat. He loves the sauce of the canned Weruva food, for example, but leaves all the meat. I have occasionally (maybe 1-2x/week) been cooking him a small piece of the fish I buy for myself – organic, wild-caught Alaska salmon, which he loves and will actually eat up. Is that ok if I’m avoiding farm-raised?

    • For a cat with kidney disease, the most important thing is that he eats anything at all, even if it may not always be the best quality food. I think you’re okay with feeding him the wild-caught salmon, especially since he loves it.

  7. What about sardines or herring? These are sustainable, extremely low in mercury, bottom feeders, high in omega. Tiki Cat has a sardine canned food that is also the lowest in fat, highest in protein of all their canned meals.

    As a pescetarian, we are also always looking for humane, sustainable and non-polluted fish, and have found sardines and herring plus small amounts of wild-caught salmon to be the safest and best for the environment.

    • You may need to do some research (contact the manufacturer) to be sure that the sardines and herring used in cat food meet all your requirements, Saffron. Tiki Cat in general is a good brand, although I stick with the poultry flavors.

  8. My cat is 18 years old, and he has always been allergic to fish. So, I am happy to know this information for future kitties, but don’t have to worry about it now.

  9. how do i stop my cat from eating fish?

    I adopted my cat from the street and he only wants to eat fish. he usually eats boiled fresh fish and fish based canned food but recently he got urinary track problem and the vet gave him Royal Canin Urinary SO dry diet. he’s been eating it for 4 weeks and now he doesnt want it anymore, he threw it out again as soon as he eats it.
    so i tried to switch to Wellness and Holistic Select canned food but he doesnt want to eat those at all, even the fish based ones. the only canned food he wants to eat is Whiskas ocean fish and the tuna ones.

    so now his meal usually consist of fresh fish (usually either one mackerel fish or two sardines a day), boiled, only the meat part, and about 1/4 Whiskas canned food a day.
    do you have any suggestion how i can get my cat to eat anything other than fish? i tried mixing the Wellness and Holistic Select canned food with Whiskas or fresh fish, but my cat still doesnt want to eat them.

    and what do you think better, whiskas canned food or fresh fish meat? i’ve been so frustrated trying to get him to eat anything other than fish and nothing works. i’m worried that his urinary problem will return if he keeps eating fish.

    • I would continue to work on transitioning your cat away from fish, Cheryl, and I most definitely would not feed raw fish except as a VERY occasional treat. Try some of the tips in this article, even though it’s geared toward weaning your cat off dry food, it should work with weaning a cat off any diet that’s not healthy:

      To answer your question about Whiskas vs. fresh fish: even though I don’t like some of the ingredients in Whiskas, it’s a better choice than just feeding fish. I’m concerned that your cat is not getting enough taurine and other vital nutrients.

      If he continues to vomit immediately after eating, there may be something else going on.

  10. My cat Wilson is allergic to fish, it causes his hair to fall out and a lot of itching. I wonder if he would have the same problem with the greenlip mussel?

    • Gail, that’s an interesting question. Green lip mussel is actually used to treat allergies, so I’m thinking it wouldn’t be a problem, but I’m not sure. I’ll try to get an answer for you.

        • There are some GLM supplements that are said to be safe for pets and people with fish and shellfish allergies – it depends on the manufacturing process and whether the allergy causing protein molecule is removed or not. I’d check with your veterinarian before giving any supplements, just to be on the safe side.

  11. I am trying to wean my cat Billy off of dry food–it has been a battle of wills– and I have settled for him eating half dry and half canned food. Unfortunately, the only canned food he will eat are the Natural Balance fish flavors. I agree Caren, now what?

    • Debbie, that’s wonderful that you’re making progress in weaning Billy off of dry food! I’d encourage you to try and introduce other flavors. One of the brands that has some very tasty flavor combinations is Weruva. I’m hearing great things about this brand.

      However, if it’s a toss up between him eating no canned food and eating only fish based canned food, he’s still better off with canned food.

  12. Uh-oh! Now I have a REAL dilemma. Cody and I were at the vet last week. As you know, Cody has been eating Royal Canin Rabbit since last August. My vet informed me that Royal Canin is probably phasing out their rabbit food (I am inclined to think it is due to political reasons).

    When I asked what I should switch Cody too he said a limited ingredient brand such as Wellness, Nature’s Balance (which I never have heard of) and recommended I switch to FISH, specifically SALMON and WHITEFISH. Cody can have no beef or chicken, etc. NOW what do I do?

    • Caren, Nature’s Variety Instinct has a rabbit diet. Ruby and Allegra eat it occasionally, and they love it almost as much as they love their raw rabbit.

      Since your vet is taking the limited ingredients approach, you have some some other options. You can try duck or venison. I believe Natural Balance has a venison version. So does Nature’s Variety.

      However, since Cody likes the rabbit, I’d start with the Nature’s Variety Instinct Rabbit formula.

      I hope this helps!

      • Hi Ingrid and thanks for answering! The problem is, the vet specifically said fish. The question is do I listen to my vet? That is the dilemma. Also, I didn’t see Nature’s Variety or Natural Balance at Petsmart. I featured Nature’s Variety on my blog but I have never even heard of Natural Balance.

        I was at Petsmart last week and didn’t see either of them.

        I need a brand that is accessible that I don’t have to order online.

        I believe my vet only carries Royal Canin.

        • Unfortunately, you won’t find these brands at Petsmart. Only you can decide what’s right for you and Cody. Do the research, talk to you vet, and then make your decision based on all the information.

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