10 Best Macro Algae for Reef Tanks

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Macro algae are large types of algae that you can put into your reef tank. There are two types of algae you can get: micro and macro algae.

Micro algae are really small algae that can only be seen with the help of a microscope, while the macro algae are larger algae that can be seen without a microscope.

Both types can be vital to your reef tank. However, you don’t want any of these two types to spread too much in your tank.

Both macro and micro algae do not have roots or stems; instead, the macro algae perform all the important life cycles through their cells. Macro algae can be vital for a healthy reef tank, as they perform photosynthesis in your tank.

There are several types of macro algae that you can get, and they are all based on color. We know green macro algae, brown macro algae, and red macro algae.

What you do need to pay attention to is that you do not put macro algae together with micro algae, because the macro algae will get all the nutrients and necessary chemicals like nitrates first, because they need significantly more nitrates than the micro algae.

Therefore, the micro algae will not be able to sustain themselves in the long term and will therefore die. The macro algae will eat up all the nutrients away.

In this article, we will be taking a look at macroalgae. Whether you are looking for some macroalgae to put in your tank, here are the 10 best macroalgae to put in a reef tank.

1. Chaetomorpha

The chaetomorpha is known as a very good type of algae to put in your tank for many reasons. It can be seen as purely ornamental due to the fact that it looks great, but it has many other benefits.

First of all, it can be a good hiding place and habitat for many crustaceans. However, the primary role of the chaetomorpha macroalgae is to reduce and optimize the number of excess nutrients in your tank, such as nitrates and phosphate.

A good feature of the chaetomorpha is that you can grow them as a soft bed on the bottom of your tank. It will not reproduce really rapidly which is a good thing as they will not emit as many chemicals that can cloud the water in the tank, but they can be aggressive if they are thick and can be actually dangerous to some corals in your reef tank.

However, they will reproduce from time to time, which will cloud your water.

All in all, chaetomorpha is one of the more popular macroalgae that you should consider for your reef tank.

2. Green Gracilaria

Green Gracilaria

Green Gracilaria

The green gracilaria, or the green ogo gracilaria, can be a pretty good addition to your tank as well. The dark green color of the macroalgae will bring an attractive appearance to your tank and it will surely liven it up.

It is a fast-growing macroalgae, which means that it represents a great type of algae to be used as feeding algae for the creatures in your tank. You can even grow the algae separately and then put it in the tank.

Like the chaetomorpha, the green gracilaria can too be used as algae that will regulate the excess nutrients in your tank – nitrates, and phosphates.

This type of algae is great because it grows quite quickly, but it does not mean that it will present a problem for you; in fact, you can trim the excess algae and then feed it to the fish in the tank. It will make for a very nice treat.

3. Ulva (Sea Lettuce)

Ulva (Sea Lettuce)

Ulva (Sea Lettuce)

Also called the sea lettuce, it is widely accepted that this type of macro algae should belong to the Ulva. It is very well-known because of the fact that it is edible and that is very commonly found in the seas around the British Isles, France, and Denmark.

The best way to grow them or the way they grow is that they attach to rocks and then they grow from the rocks. It has a membrane that attaches to the rock and then allows it to grow.

Sea Lettuce is often seen as a nuisance in the natural habitat due to the rapid growth; but in a reef tank, it is actually quite beneficial. Not only does it regulate the excess nutrients in your tank, but it also presents a good source of food for your fish.

This is especially important to note if the Ulva grows very rapidly in your tank; you can simply use it as food for some fish in your tank.

4. Blue Hypnea

Blue Hypnea

Blue Hypnea

The blue hypnea is a great option for those who are looking to add a bit of variety to their tanks. It is a blue-colored type of algae that is primarily used as an ornamental piece in reef tanks due to their colors.

It has a peaceful character and also the fact that it does not grow very rapidly is great, as you will not need to control its growth as often as with some other algae.

The blue hypnea attaches to the pieces of the substrate with its membrane-like structure and grows from there. Like the other algae on this list, it hasn’t only got ornamental purposes.

In fact, it has some very good uses, such as food for herbivores in your reef tank and as a natural filter to filter out the excess nutrients. So, you get the benefits as an ornamental piece as well as other benefits of the algae.

5. Red Gracilaria

The red gracilaria will display some amazing colors that will surely liven up your reef tank. It will be seen in a red color that is slightly transparent.

This type of algae is a great way to not only have a good ornamental piece in your reef tank but can also be used as food for herbivores in your tank.

If you have some invertebrates in your tank, they will absolutely love the red gracilaria. They will use it as a hiding spot, and even as a living habitat.

If the algae grow too much for your liking and start taking up too much space, you can simply trim them and feed them to herbivores in your tank.

Of course, you will get all the other benefits that algae provide.

6. Agardhiella


Agardhiella is another good choice for a reef tank. This type of macro algae will provide you with dark red colors and will surely make a difference in your tank.

The structure of the agradhiella is quite interesting – it grows in branches that are unevenly distributed, which makes for a very interesting sight and one that will certainly impress.

In addition to having an interesting appearance, this type of macro algae will bring several other benefits that algae can bring to your tank.

It won’t really grow as quickly as some other algae, but can be used as food for fish; it can be brought in as purely ornamental, or to take advantage of the many benefits that will improve the quality of the water.

7. Brown Gracilaria

Brown Gracilaria

Brown Gracilaria (source)

The brown gracilaria (Gracilaria parvispora) is another sub-type of the gracilaria macroalgae. It comes, unsurprisingly, in brown color, which can vary according to conditions in the tank.

If the water is flowing quickly and the lighting is strong, it is more transparent and brownish. If the water is dim and flowing slowly, then you will see a much darker shade of brown.

The maximum size of these algae is about 30cm (source); if it grows too much, it can be trimmed easily and fed to your fish. The brown gracilaria can primarily be found in Hawaiian waters where the motion of the water is slightly lower. Which brings out the darker shades of brown from these algae.

You can choose the brown gracilaria for the many benefits that it can bring or as an ornamental piece.

8. Pom Pom Gracilaria

Sometimes referred to as the red bush macroalgae, the pom pom gracilaria is definitely a very pleasant sight for marine tank owners.

Of course, it is known as an effective exporter of excess nutrients in the tank and is also revered by the fish tank owners who have herbivore fish species in the tank because they can represent a good food source for those fish.

The pom pom gracilaria should be kept in proper living conditions; if those are provided, then you can expect really strong and quick growth.

The algae are quite hardy and will last you a long time. And will adapt to various conditions in the tank.

Best of all is the fact that it can bring bright colors to your tank as well as all the benefits that algae can bring.

9. Halimeda



The Halimeda macroalgae is a type of green macroalgae that is made from calcified green segments. This makes it inappropriate to use as a type of algae for feeding your herbivores because it contains calcium carbonate which makes these algae inedible.

But these green algae certainly have a very interesting look to them. They grow out in a sort of leafy fashion. The Halimeda is mainly found in the waters around Australia, especially near the Great Barrier Reef.

It is composed of calcified discs which are connected by flexible joints, making for a very interesting appearance. These algae are best used as ornamental pieces in your reef tank.

10. Caulerpa

Last but not least that you should consider for your reef tank is the Caulerpa algae. It is a very interesting type of algae due to the fact that it consists of only one cell. Making it one of the largest single-cell species in the world.

It is often seen in the culinary world. Caulerpa is not unusual to see it in Japanese or Indonesian cuisine, where it is also known as green caviar or even sea grapes.

In the Mediterranean, it has become one of the invasive species of the sea. It tends to spread quite quickly, and can be aggressive towards other algae. But you can control the growth of these algae and regulate them.

Of course, they do bring several benefits that are desired for reef tank owners. Such as good water filtration and removal of excess nutrients in the water as well as providing some great colors for your tank.

Why Grow Macro Algae in Your Tank?

If you are a reef tank owner, you have a choice of either growing micro or macro algae in your tank or refugium. There are benefits to both; if you opt for the macro algae, you can expect some really good benefits (depending on the type of algae, of course).

In general, the vast majority of these algae will bring you a source of natural filtration. These algae will clean up your tank of excess waste nutrients that might accumulate. This is possibly the biggest plus of the macro algae.

Many of the macro algae out there have a very interesting and appealing look to them. So, not only are they good as a natural filter. They will make your tank more interesting and appealing by adding some interesting colors and variations.

Other benefits of such algae are their use as a living habitat for some species in your tank. As well as a possible source of food for some herbivores in your tank. If you manage to control the growth of some of these species, the macro algae can bring you a lot of benefits.


In this article, we have taken a look at some of the best macro algae for your reef tank. As we have already established, these algae can be really beneficial for your tank for many reasons.

Before you choose, you must, of course, consider what types of fish you have in your tank and whether these algae would grow too quickly for your liking.

Hopefully, you have learned a lot about macro algae and that now your choice is much easier.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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