A Look at Seven Great Red Macroalgae For the Refugium

Red macroalgae Washed up on the shore.

It’s been a looong time since there was a “typical” refugium. And even if there was a typical sort of refugium today, it wouldn’t look exactly like the one of yesterday. One very notable change is the greater diversity of macroalgae used, including Red Macroalgae. Gone are the days where nearly everyone with a refugium had a monoculture of Caulerpa growing under their tank. Now, depending upon intended use and even the keeper’s aesthetic tastes, some combination of green or red algae might be cultivated together.

Though green algae (i.e. chlorophyte) genera such as Caulerpa and then Chaetomorpha have dominated the refugium in years past, red algae (i.e. rhodophyte) genera such as Gracilaria and Halymenia are clearly gaining prominence as of late. Part of this trend is surely due to changing uses and tastes. But it may also just be due to a better selection in the trade of macroalgae in general and of red macroalgae in particular.

We here take a look at seven refugium-friendly rhodophytes and discuss why each might be appropriate for your system.

  1. Red Ogo Plant (Gracilaria parvispora).

Red ogo is a delicately beautiful macroalgae. It is between reddish and bergundy in color. Its form is thin with short but thick, bushy fronds. Red ogo is a fast-growing and hardy macroalgae when kept under proper conditions. It is also great for nutrient export in heavily stocked saltwater aquarium systems. Additionally, it is prized by many herbivorous fish keepers (especially tangs) as a healthy live seaweed food. As red ogo grows out in the refugium, older growth can be harvested and fed to herbivorous fish as a nutritious snack.

  1. Green Ogo Plant (Gracilaria tikvahiae)

Green ogo is unusual in that its green pigments are so pronounced that this rhodophyte appears more verdant than ruddy in hue. Like red ogo, green ogo is normally very fast-growing and hardy. Furthermore, it is also a great vehicle for aggressive nutrient export. Additionally, it is prized by many herbivorous fish keepers (especially tangs) as a healthy live seaweed food. It grows well with and looks nice with red ogo.

  1. Thick Red Ogo Plant (Gracilaria sp.)

Thick red ogo resembles the related red ogo plant, but has somewhat thicker blades with a stockier and spindlier appearance. Its pink to deep red colors add color and beauty to an otherwise plain refugium. This one is a bit more rare than its lacier counterpart, so get it when you can!

  1. Spike Sphere Macroalgae (Gracilaria tikvahiae)

Spike sphere macroalgae is a very attractive seaweed. This macroalgae is a bit more slow-growing and most appropriate for more established systems with lower dissolved nutrient loads. This particular Gracilaria is often chosen by aquarists primarily on the basis of its appearance. Additionally, while not quite as palatable (soft) as the ogos, freshly harvested spike sphere macroalgae can nevertheless be offered as a live seaweed food.

  1. Pom Pom Macroalgae (Gracilaria hayi)

The pom pom macroalgae (sometimes called the red bush macroalgae) has rather broad, flat, leaf-like blades. This is the Gracilaria most oft used for ornamental purposes. While a bit less palatable than most of its congenerics, pom pom macroalgae can be offered to determined herbivores such as rabbitfishes, sea urchins, etc.

  1. Leafy Sphere Macroalgae (Halymenia maculata)

Leafy sphere macroalgae closely resembles other members of its own genus as well as many Gracilaria spp. It is most distinctive in its heavy blades and its highly blotchy pink, purple and deep reddish coloration. In fact, though it grows well in the refugium, it can also be used in the display tank (if no large herbivores are present) as an ornamental. Halymenia maculata grows either free-floating or attached to rock. This species grows slowly (for a seaweed) and thus requires less frequent harvesting than some other refugium macroalgae. It does prefer good water quality and stronger water movement.

  1. Dragon’s Tongue Macroalgae (Halymenia dilatata)

Dragon’s tongue macroalgae is one of the most highly sought-after refugium macroalgae species. It is prized by marine aquarists as an ornamental macroalga due to its pink to bright red coloration and deeply furcated, flame-shaped fronds. Though it is quite attractive in the main tank, it can be used in the refugium for steady (but slow) nutrient export similarly to leafy sphere macroalgae. It prefers areas of moderate to high water flow. Halymenia dilatata tolerates lower light conditions and can flourish in shadier or deeper parts of the tank. It can grow either free-floating or attached to rock (attached individuals can grow to heights of over 1.5 feet in the wild!).

Red Macroalgae: Grow Them All!Handfuls of Red Macroalgae

Different aquarists have different reasons for wanting to grow macroalgae. Even just among the red macros, there are some species that are better suited for certain purposes than others. For example, if you have a newish refugium (or even a new system) and nutrient levels remain high and/or unstable, you might want to go with an ogo (or mixture thereof). You might likewise select an ogo if you intend to use harvested material as a fish feed. On the other hand, say you have a more established system and your nitrate/phosphate levels are mostly under control; you then might want to enjoy of the more exotic looking, broader leaf types such as pom pom macroalgae.

Most aquarists will start with one or two good nutrient exporters, but add more colorful, interesting and challenging forms as the system matures. Eventually, you could end up trying out all of them as your needs change and your collection grows!

419 thoughts on “A Look at Seven Great Red Macroalgae For the Refugium”

    1. This is great info for those who keep a refugium!
      What would you recommend for folks who want to use macroalgae as part of their display tank? How should these be used ornamentally, especially if we have corals too?

      1. greg.chernoff

        Great Question! Always look for slower growing “super pretty” species for display, stay away from chaeto or sea lettuce, and look into getting something like dragons tongue or blue hypnea!

        1. I’ve always been interested in ornamental Macroalgae and it’s uses for scaling tanks. Great article about the different species!

        1. I’m working on how to incorporate a refugium, as I do not have a sump. Hang on back isnt all bad, but I’m trying to figure out a diy in-tank option.

      2. I had a Dragon’s Tongue in my DT while it was in a fallow period while I dealt with an ich outbreak, and it was beautiful! Unfortunately, either my cleaner shrimp or my hermit crabs ate it! 🙁

      3. Nadya Lazarev

        I had Macroalgae in my display tank. Over the period of six months Pom Pom Macroalgae, red ogo and dragon’s tongue were eaten by my fish, sea urchin and green emerald crabs. When all those fancy Macroalgae were eaten, one of green emerald crabs started to munch on chaeto. Chaeto survived and looked pretty cool in a ball in the corner of the tank. My mandarin loved that corner; I guess because the copepods were mostly there. I finally build a sump and moved chaeto to the refugium. I have ordered more Macroalgae from AlgaeBarn to add to the refugium. I have never had any pests or issues from AlgaeBarn. I won’t add Macroalgae to the display tank as a decoration for now; I will just trim the overgrown algae and feed my creatures. When fish, sea urchin and crabs ate macroalgae, they cut it in pieces and created a little mess, so I had small pieces of macroalgae floating around the tank and getting stuck into the equipment.

  1. A variety of macros in my refugium is another reason for success from algae barn. I love the red dragons tongue and the clean chaeto!! Mix it up all algae do different things!!!

  2. Can’t wait to try one of the best companies in this business to help me get started on my goal to raise a happy Mandarin.

    1. greg.chernoff

      US?!? Thank you so much Peter! We can’t wait to get you a little captive bred mandarin who eats frozen brine eggs and can o’ cyclops and live nano brine… one of our little mandarins is sure to live FAT and happy with you!

  3. Charles Wheeler

    I’m literally in the process of building a refugium add on for my AIO system. Look for an order in the near future.

  4. Charles Wheeler

    I’m literally in the process of building an add on refugium to my AIO system. Look for a order in the near future!

  5. Charles Wheeler

    I’m currently building an add on refugium for my AIO. I’ll be ordering sooner than later.

  6. I tried Red Macroalgea but it didn’t stay together and ended up traveling into my return pump.

  7. Dwayne Newell

    I was looking to split my refugium so two types of algae can be grown for a heather environment

  8. Dwayne Newell

    I was looking to split my refugium so two types of algae can be grown for a heather environment to copepods to grow.

  9. Hello there,
    I really do enjoy coming onto your webpage and reading more about building a refugium. Can you help add which macroalgae grow and consume faster than others (from the hardy to the least hardy)?

  10. Would really like to look into using it in an ornamental way. Been needing to do more research this was help, as was one of the answered questions in the comments

  11. So many varieties with so many different applications… If you set it up right, macroalgae can almost provide a self-sustaining food snack for so many tank inhabitants!

  12. Quick question, will the Red Ogo stick together like Cheato does? I once had a red macro algea which I now can’t remember the name of and it spread all over my sump because it wasn’t holding together.

  13. Cardell White

    So I have chaeto and pom pom macroalgae growing in my fuge. If i put put say the pom in the display, will other crustaceans eat it?

  14. bourgetrider06

    Just ordered 48oz of Pods and 48oz of Ocean Magik to add to the Chaeto in our fuge for our 150G…

  15. How well do the red goo use up nutrients in the water compared to the chaeto…. since I’ve been reefing chaeto was always said to be the most common but I’m thinking about some bio diversity when it comes to plant and coral life in my 40g salt/starter reef. Tank has been running for almost 2 years!!!

  16. Down the road I’d love to have a display refugium with multiple macro algaes and sea horses and mandarins. It will be a throwback to my planted fresh water tank days while still being a beneficial nutrient export for the main reef tank. For now I stick with standard issue cheato in my sump refugium.

  17. I have Chaetomorpha in my refugium and it works well at helping keep nitrates and phosphate low and all my pods are living in it.

  18. I love all your biological marine creatures and I love how you sell a variety of pods and algae. Keep up the good work! 😉

  19. This is great info! When I started up years ago I thought it was not fair how freshwater had lots of plant options and saltwater did not. It is great to see so many more options!

  20. Never really knew how beneficial macros are. Ever since I started growing macros in my reef tank, I’ve seen an explosion in my copepods.

  21. I’m commenting to enter a give-away but while I’m here, does anyone know if there are different light requirements for the various algaes? I currently grow Chaeto in my fuge and would love to add some color but I’m unsure on the light requirements for the different types.

  22. I have had some red pom pom in my fuge for a while now and it actually grows compared to chaeto which I cant manage to keep alive. Great info for sure

  23. any suggestions for keeping red ogo, I have attempted to keep it before without luck but haven’t had any issues with Ulva, red mangroves, cheato

  24. any suggestions for keeping red ogo, I have attempted to keep it before without luck but haven’t had any issues with Ulva, red mangroves, cheato

  25. I use both your Red Ogo & Pom Pom Gracilaria along with Clean Chaeto. It’s great stuff! Definitely need to try out some of the others! 👍

  26. I am getting ready to create a 120 display refugium, what macro algae do you recommend? I want to stay away from the fast growing so it doesn’t fill up too fast since I want it to be a display.

  27. At what point do any of these start trying to outcompete other species? Is there a limit to the amount of macros you can grow in one system?

  28. I’ve tried macro at least 10 times in my display tank but having herbivores that eat everything they aren’t supposed to eat frustrating. It’s either my foxface or naso hitting the stuff that is pretty and or my matted file fish pair that decimates everything else.

  29. iv had the chance to use some of these awesome products and I have nothing but good things to say about them always just the right amount I need and always in the most excellent quality that I expect when adding anything to my reef tanks thanks Algae Barn for the great products that I look forward to using for many years to come.

    1. You can keep multiple macroalgaes in the same refugium. They may “grow” into one another, but they will not harm each other.

  30. These are wonderful for refugiums! I like to grow cheato and red macro algae for the color contrast because I have a hob refugium.

  31. Very helpful. I have tons of chaeto in my fuge but I heard it’s best to have a few different kinds so I’m considering adding some reds.

  32. I love your macro algae’s! I recently stocked up and like to grow them out in my display for beauty and efficiency.

  33. This a super informative article for someone like myself who doesn’t have a refugium yet but is planning one. I plan on growing and keeping several of these algaes in my refugium. Thanks algaebarn for the knowledge!!

  34. I love Algae Barn. They have helped me so much stocking my 230g reef tank with pods and my refugium. Their packaging is outstanding and they are very quick returning questions.

  35. A bunch of beautiful macro algae conveniently in one place for new and old reefers who are trying to pick the perfect macro algae for there reefs.

  36. Entering algae barn contest for pods! Commented twice already not sure why it hasn’t been checked off my box

  37. I purchased Red Ogo, Sea Lettuce and Chaetomorpha plus an urchin from AlgaeBarn a month or so ago. Great additions and fantastic packaging! Looking forward to shopping again.

  38. I love Algae Barn. They have helped me so much stocking my 230g reef tank with pods and my refugium. Their packaging is outstanding and they are very quick returning questions.

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