Should You Feed Your Reef Tank Phytoplankton? Or nah?

There are 3 types of Phytoplankton:

  • Diatoms
  • Dinoflagellates
  • Desmids

There are a lot of species in the ocean that consume Phytoplankton. It’s pretty much the foundation for the marine food chain. I was first introduced to this stuff in science class when I was in grade school. From there I ended up culturing 1,000s of gallons of this stuff in our aquaculture facility.

Aside from being a food source, Phytoplankton is currently being researched for a bunch of different uses including bio fuel. Due to certain species exponential growth rates, such as Tetraselmis, this stuff could eventually power our cars, our homes and even entire cities. Only time will tell.

In the aquarium hobby Phyotplankton is used to feed a variety of species as well as for breeding projects. There is a lot of debate on whether or not this stuff is essential to your reef tank. Let’s take a closer look at this stuff and you decide from there if you want to use it in your reef tank or if you are up for the challenge of culturing it yourself for your breeding projects.

Here’s the basics of the species that I personally have cultured:


This species has the ability to accumulate high levels of polyunsaturated fatty acids. Basically it is an energy-rich food source for fish larvae, Copepods and Rotifers. You can grow this species relatively easily.


This species has a very high lipid level. It’s amino acids stimulate feeding in marine organisms. It has a very fast growth rate and it is moderately easy to grow.

Isochrysis galbana

This species is very sensitive but it contains Omega 3s which are an essential nutrient. It can crash really easily if you are culturing it in an area where there are other species of Phytoplankon or zooplankton. So you will need to be very careful with not getting any of the other species near it if you are culturing it. Also, be sure to thoroughly sterilize any equipment that you are using in order to culture it. Once we added this species to our Nanno and Tetra algae blend to feed our Zooplankton we noticed a huge, positive difference in the development of the Zooplankton as well as the positive health effects on the Seahorse babies that ate them. This is good stuff even though it can be difficult to grow.

On average a bottle of Phytoplankton Blend can cost about $20. And if you are dosing your tank with it, it can get expensive. There are TONs of videos on YouTube that will show you how to grow this stuff for free but the issue is that most of these people grow their Phytoplankton – which the zooplankton and filter feeders eat – in plastic bottles. Plastic bottles contain all kinds of chemicals that breakdown under sunlight – which is exactly the type of light that you use in order to grow Phytoplankton. So if you grow it in plastic bottles, your zooplankton, corals and fish are ingesting harmful chemicals. On top of that, if not grown correctly, you can accidentally culture a bad bacteria that can wipe out your entire reef tank and even cause a Cyanobacteria outbreak. Not a good time.

So yes, this stuff is great for a reef tank that contains species that are filter feeders and that consume zooplankton but only if it’s sustainable cost wise and cultured correctly.

Recently, we created an online course that shows you exactly how we grew our cultures in our aquaculture facility. We even scaled down the instructions and protocols from the 5 gallon culture vessels that we used in our aquaculture facility to these flasks which you can purchase on Amazon for about $20.

The course is very comprehensive and all of our tips and tricks are included. Including how to eliminate any unfavorable bacteria that may result from the culturing process that you could unknowingly expose your tank to if no precaution is taken.

So if you are interested, you can enroll in the course here:

What are some other things that you have seen Phytoplankton used for? Let me know in the comments below.

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