Phytoplankton powder for dogs on a white surface

Phytoplankton For Dogs: Benefits, Dosage & More

One of my readers, Alisson, recently asked me if I could talk about phytoplankton for dogs on the blog, so that’s what I’m going to cover today.

She specifically asked if she can use phytoplankton in place of fish in her raw dog food, and if so, what the dose is.

Besides answering those two questions, I also point out:

  • The difference between phytoplankton and kelp
  • What the benefits of phytoplankton are for dogs, and
  • Where to buy it.

Phytoplankton For Dogs

Phytoplankton for dogs

Disclaimer: This blog post contains affiliate links. I may earn compensation when you click on the links at no additional cost to you.

First things first, phytoplankton are microscopic algae that are about 9 times smaller than a red blood cell!

They’re primarily associated with marine life, and all ocean animals rely on it, including fish.

Important to understand: Phytoplankton is not fish, but it’s what fish eat!

That said, there are certain types of phytoplankton that are beneficial for dogs (and humans!) as a nutritional supplement.

Specifically, marine phytoplankton, such as Nannochloropsis gaditana and Thalassiosira pseudonana.

Marine Phytoplankton Benefits For Dogs

Marine phytoplankton is rich in essential nutrients, including Omega-3 fatty acids (mostly EPA = Eicosapentaenoic acid, but also some DHA), amino acids, Vitamins E & C, trace minerals, antioxidants, chlorophyll, and other bioactive compounds.

These nutrients nourish the cells directly without having to be digested, and help support various aspects of your dog’s health, including:

  1. Healthy skin and coat: The Omega-3 fatty acids in phytoplankton contribute to a shiny coat, reduce inflammation, and alleviate certain skin conditions like excessive itching and shedding.
  2. Joint health: Phytoplankton’s Omega-3 fatty acids have anti-inflammatory properties that help reduce joint inflammation and support overall joint health.
  3. Immune system support: The vitamins, minerals, and antioxidants found in phytoplankton can help boost your dog’s immune system and protect against oxidative stress.
  4. Energy and vitality: Phytoplankton’s nutrient profile contributes to improved energy levels and overall vitality in dogs.

Keeping all that in mind, it’s essential to choose high-quality, human-grade phytoplankton supplements.

Next up is where you can find these!

Where To Buy Phytoplankton For Dogs

The following products include 100% pure phytoplankton, and you can use them both for your dog as well as for yourself and your human loved ones:

Can I Use Phytoplankton In Place Of Fish for Dogs?

As you may know if you’ve read some of my raw dog food blog posts, I add whole fish to Wally’s raw meals.

Specifically, mackerel and herring.

That said, I use phytoplankton when I’m out of frozen whole fish for Wally. The kind I buy here in Germany is from the Netherlands.

So yes, you can replace fish or fish oil with phytoplankton.

And if your pup is allergic to fish in general, you can try giving them phytoplankton instead.

Wally's raw dog food features marine phytoplankton
Wally’s raw dog food features a bone-in rabbit chunk, turkey meat, deer liver, beef testicles, a duck egg and marine phytoplankton

Phytoplankton For Dogs Dosage

Since phytoplankton has double the amount of Omega-3s than fish oil, dogs only need very little of it on a daily basis.

According to Dogs Naturally Magazine, you can give any sized dog 1/16 of a teaspoon worth of phytoplankton.

You can either use a 1/8 teaspoon and divide it in half to get to 1/16 of a teaspoon.

Or you can fill a 1/4 teaspoon with phytoplankton, then divide it in half, and divide one half in half again.

FYI: 1/16th of a teaspoon is considered a pinch.

I’ve also found slightly more detailed daily dosage instructions on the packaging of Mr. Ros Marine Phytoplankton for dogs:

  • 1/16 teaspoon for small dogs
  • 1/4 teaspoon for medium dogs
  • 1/2 teaspoon for large dogs

I personally use this approach when I measure out Wally’s phytoplankton allowance.

That’s because it makes sense to me to make the amount you feed dependent on your dog’s weight.

Since Wally’s a medium size dog and weighs in at around 38 lbs, he can have 1/4 teaspoon of daily phytoplankton.

But only when his meals don’t feature any raw fish!

Measuring out my dog's dose of phytoplankton
Wally’s and my marine phytoplankton from our neighbor country, the Netherlands

What’s The Difference Between Phytoplankton and Kelp for Dogs?

Now, both kelp and phytoplankton are important marine organisms, but they differ in terms of nutritional composition and the roles they play in marine ecosystems.


Phytoplankton are microscopic, photosynthetic organisms that mostly float in the ocean and are the foundation of marine food chains.

These organisms are responsible for a significant portion of the Earth’s oxygen production through photosynthesis.

Phytoplankton is a primary source of marine nutrients including Omega-3 fatty acids, and plays a crucial role in supporting marine life, including fish.

Phytoplankton vs kelp for dogs


Kelp is a type of large brown algae that grows in underwater forests along coastlines.

It’s very nutritious and contains various vitamins, minerals, and dietary fiber.

Kelp is also very rich in iodine, which is important for thyroid function, as well as other minerals like potassium, calcium, and magnesium.

The biggest difference between the two is that phytoplankton is richer in Omega-3 fatty acids, and kelp is richer in iodine.

Phytoplankton For Dogs: Bottom Line

Phytoplankton is a nutrient rich microscopic algae, which makes it a superfood for dogs (and their humans)!

You can add it to your dog’s (raw) dog food instead of whole fish or fish oil. The really good news is that you can actually give it to dogs who don’t do well with fish!

Replacing fish in homemade raw dog food with this whole food
Replacing fish in Wally’s raw meals with marine phytoplankton

While it’s a bit more on the expensive side, it lasts a while since dogs only need very little of it.

I personally enjoy eating fish, but I’ll also add some phytoplankton to my goat yogurt, along with a variety of nuts and fresh fruit.

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Barbara launched her blog K9sOverCoffee in 2014 and has been feeding her dogs raw dog food since 2015. As a former professional dog walker, she’s passionate about balancing species-appropriate exercise with healthy dog nutrition. Barbara is raw dog food nutrition certified from “Dogs Naturally Magazine” and the author of several e-books about minimally processed, balanced raw dog food.






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