A Yellow and Blue Tang in a Marine Aquarium

Cultivating Ogo and Sea Lettuce for Your Tangs

These days, it seems that most marine aquarists are reef aquarists. And reef aquaria almost always house one or more tangs. This should seem reasonable enough, as representatives of this sizeable fish family (Acanthuridae) are found in abundance in pretty much every shallow water coral reef ecosystem on Earth. But their strong presence in the wild is hardly the only reason that they are so often selected for display by saltwater aquarists. Many of them are beautifully (some you could say stunningly) colored and patterned. They are relatively hardy and readily adaptable to normal captive conditions. These are also very bold, active fishes with what some describe as “personality.” Tangs are especially rewarding for keepers who love to feed their fish, as they are notoriously enthusiastic eaters.

One notable characteristic of the family in general, and members of the genus Zebrasoma in particular, is their heavy reliance on algae in their diets. This is particularly remarkable in that algae grow in very meager quantities on most coral reefs. A hyperactive fish such as the yellow tang (Zebrasoma flavescens) consequently must graze nearly all day to meet their basal dietary needs.

Under the usual captive conditions in home aquaria, things might be a little different for a tang with regard to diet. Most significantly, much of what they consume is from packaged dry or frozen fare (not live) and thus likely has lost some palatability and nutritional quality during processing. Not quite perfectly natural in terms of taste and mouthfeel! And, prepared diets almost always have a significantly higher protein/carbohydrate ratio (even those “herbivore” formulas) than the natural tang foodstuff. It fortunately is possible to acquire the real thing–fresh, live seaweed! The best way to accomplish this is to grow it yourself in a great big planted refugium.


Getting Your Grow On

Yet one more thing that has contributed to the enduring popularity of tangs amongst aquarists are the animals’ habits of consuming nuisance turf and hair algae. Many cite algae control as the biggest reason they keep these animals. But, very quickly, even a single specimen will pretty much eradicate all algae it can reach and begin to grow hungry. The solution? Cultivate a large, lush seaweed bed in an area that is designed specially for plant growth (per substrate, lighting, etc.): A planted refugium!

Let’s just start by pointing out that there are numerous reasons to install a refugium on virtually any marine aquarium system. One common use is to promote large populations of resident microcrustaceans such as copepods (i.e. a place where they can feed, mingle and breed without constant harassment by predators). Macroalgae create a perfect biogenic habitat for pods of all kinds. As they grow, macroalgae also sequester or “absorb” nutrients from the water, thereby competing aggressively with nuisance algae throughout the entire system.

But there is one use of macroalgae that is–despite being so oft overlooked–of extreme value to those who have and love a tang. As the plant material starts to overgrow the environs of the refugium growth chamber, portions of the crop are harvested. This freshly harvested material is customarily thrown out with the trash. What would your tang think, watching aghast from behind a glass panel as you toss out piles of that delicious seaweed… without offering a mere pinch..?

If an edible macroalga is selected for refugium use, then your tangs just scored a regular source of their favorite nutritious snack (so long as you give it to them!). The overall nutritional quality of their diet will be improved yet further if more than a single species/type of seaweed is served.

The Perfect Palatable Pair

Let us just begin by saying that tangs have different preferences for different kinds of macro. Though wildly popular in the hobby on account of its excellent capacity for nutrient removal, Chaetomorpha is definitely not a favorite of tangs or herbivores in general. Therefore, while it is perhaps the best choice for algae reactor applications (where it resists compaction due to its tough, wiry form), this macro is not so great as a live food plant. The reason? It’s like eating a scouring pad. Chaeto is simply too tough for the fish to easily chew.

Guess what? There are not just one but two incredibly hardy macroalgae species that sequester nutrients at just as high a rate as chaeto and are extremely palatable to fishes. When you vary the animal’s diet by using more than a single source species, you provide a better diet compared to either species alone. And even though we’re mainly talking about mostly utilitarian applications here, it’s worth pointing out also that the two differ from each other in a complementary way aesthetically and arguably look much nicer together. This amazing duo is? The red algae red ogo (Gracilaria parvispora) and green algae sea lettuce (Ulva lactuca).

AlgaeBarn’s own Clean Sea Lettuce™ is bold and leafy and very, very green. Its broad fronds provide a massive amount of surface area for pods to forage on and hide within. This nitrate-phosphate sponge appreciates regular replenishment of trace elements (such as iron). AlgaeBarn’s fast-growing Red Ogo improves the seaweed bed structurally in that its frilly, lacey, bushy fronds act as spacers that allow for more thorough water circulation (i.e. improved aeration, waste dispersal, etc.). This trait is especially beneficial when the species is co-cultured with Ulva, as fronds of the latter have a tendency to cling together like sheets of wet paper when grown alone. Best of all, both are offered as selections in the CleanMacro™ Series of pest-free seaweeds. Your tangs couldn’t have gotten luckier!


91 thoughts on “Cultivating Ogo and Sea Lettuce for Your Tangs”

    1. Benjamin Hosaflook

      I’ve never owned a tang, as I just have a nano (10gal), but I feel like it’d be a great idea!

  1. Stefanie Grober

    We use chaeto in our sump , works great! Will have to buy some sea lettuce to grow, we’ve always fed dried seaweed

      1. Greg giambrone

        I bought some sea lettuce and ogo and Chaeto came as a hitchhiker! It’s all growing in the same fuge.

  2. Can you grow the Red Ogo in the tank or must it be in the?

    We already have a lot of Chaeto growing in our refugium. We would like to add Ulva sea lettuce and Red Ogo, would we have to get rid of our Chaeto or can all three grow together in the refugium?

      1. I have done this as well, only thing is you have to keep it trimmed or one will start to take over the other.

  3. Are ogo and sea lettuce ok to grow in display tank? I read some go algeas sexual and can make a mess in the tank. If not what algae’s are good for the D.T.? Thank you

  4. I use a refugium on my system and have a fair amount of pods, however I would like to keep a Mandarin in the future , so pods is something I’m interested in learning more about

    1. Bright grow light, good flow, and a system that produces nutrients is all you need. I tried the florescent bulb and clamp light and it was just too weak. Chaeto growth was very slow. I now run a Kessil 380 in the fire and T5 on display tank. The Kessil keeps the chaeto growing so fast that their is no nutrients in the display tank for algae to grow there!

  5. Victoria Brewer

    Good read I hope to add these to my fuge when I upgrade to a larger tank plus I will be able to have tangs to feed!

  6. I’d love to cultivate anything for my Tang to eat… He likes to grab the stuff off The return jet then he blows around like a snowflake in a flurry.

  7. I probably need to get some lettuce, but i heard it overtakes your fuge. Currently using ogo and chaeto

  8. I do not have a planted tank, but my fuge grows Red Ogo, and my tangs both eat it up, kind of like feeding veggies to your kids, just don’t tell them it is good for them!

  9. I’d love to add a refugium to my tank. I need an overflow box and a sump, but I think it would be an excellent addition. I like the idea of using macro algae to remove nitrates and phosphates.

  10. I’m my upgrade I’m designing a double chamber refugium. One for cheeto and the other for ogo and or sea lettuce. If I could have the benefit of exporting nutrients and from that I could feed my fish. That’s a win, win!!!

  11. My tank is only 60 gallons so I don’t have tangs. But I grow red ogo in the refugium for it’s other benefits.

  12. William Smithee

    I may try this out. I only have 1 tang currently, but I hope to have a “Tang Gang” by the end of this year.

  13. Great article! I have a Yellow Eye Kole Tang and will be ordering some red ogo (Gracilaria parvispora) and green algae sea lettuce. Thanks for all of the great information Algae Barn!

  14. One will frequently outgrow the other, to keep them trimmed, requires even more Tank maintenance…..

  15. Get your sea lettuce from Algae Barn and not Ebay, I made that mistake and it came with lots of other unwanted pests.

  16. I am now almost 2 months into cultivating the most beautiful red orzo and sea lettuce. My Tangs love the clippings!! They somehow know when I am trimming! Love the concept of using my own grown veggies for the kids.

  17. My tangs don’t like the sea lettuce but they LOVE the ogo so I buy it regularly; I plan to redo my refugium so I can grow it; right now it’s full of chaeto

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