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FAQs about Red Algae/Rhodophyte Identification 2

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Marine Aquarium Algae Control

by Robert (Bob) Fenner

Help Identifying this macroalgae    10/17/19
<Hi Holly>
I have this macroalgae taking over a couple of rocks in my tank. It's starting to spread to a third rock now as well. It's pretty, but I'm getting concerned it's going to be a nuisance and damage corals.
So far, nothing in the tank eats it (I thought perhaps my emerald crab or Halloween urchin would, but no). The tank is a 32g biocube, so I can't put a Rabbitfish or tang in it. Can you help me identify it and give me ideas on controlling it? It may be Fauchea laciniata, but I'm not sure.
<It appears to be some type of red macro algae, probably Halymeda floridiana; not harmful but needs nitrates to survive, you might want to test for NO3.>
It's very short and individual little leaves are attached by a single point to the rock. I'm including some pictures from when it started and current, First picture is from 9/12 and second picture is from one month later, 10/12.
Interesting observation, so far, it's only growing on the man made Real Reef rock, and not on the natural live rock in the tank (so far anyway).
<It looks it prefers the smooth surface of your "man made rock." If you notice it starts to spread beyond control, you can manually trim it.>
Holly LaClair-Bogedain
<Cheers. Wil>

Re: Help Identifying this macroalgae     10/18/19
My nitrates routinely test at 2.5 (Salifert) and my PO4 tested at .043 a couple of days ago (via Hanna checker).
<Good, keep it that way. Wil.>

Cyano? Red Hair Algae 02/05/2008 Hello WWM, <<Hello, Andrew here>> My tank has had an algae problem for a while, and I believe I am slowly taking it out. First of all, I got a better Pinnacle RO unit which replaced my crummy tap water filter. <<Certainly going to help no end>> The algae has decreased significantly, but it is not quite gone yet. The one I notice the most is a long, thin, hair like red algae, that grows in certain spots mainly the substrate. I wasn't sure if this is Cyano, but I guess I won't find out until I do more water changes and more skimming. Is there a different between Cyano and red hair algae? Its my main problem. Would a Phosphate reactor help here? <<There are a few different types of red hair style algae's such as Gelidium, Polysiphonia and Asparagopsis. Providing a photograph of the algae in question would help a lot to advise what type of algae you have. And to answer the question, yes, Cyano and red hair algae's per say, are quite visually different. A phosphate reactor would certainly be a good device to add if you feel the phosphate levels are high and your unable to control them yourself>> Thanks, Joe <<Thanks for the questions. A Nixon>>

Live Rock Hitchhiker IDs (Corallimorph and Red Alga) -- 05/07/07 I purchased a new piece of live rock and a few weeks later found this growing on a piece of dried out plate coral. <<Neat>> The plate was totally bleached out and dead when it went into the tank.  These appear to be some sort of mushrooms and I have no idea what the red stuff is in the other picture. <<Mmm yes, perhaps a Ricordea species...and the 'red stuff' is a Rhodophyte though what species it is I don't know...perhaps if you have a look around at algaebase.org...>> It started out with just one small creature and has now expanded to at least 20. <<Fast grower, eh>> They are now about 6 months old. <<Mmm, ok...not atypical for Corallimorphs>> There is clearly a mouth in the middle of each one.  The stalk is soft and will extend out.  They look like Blastomussa on the top surface, but as I said the stalks extend and are soft. <<Yes...like Ricordea>> When they are fully contracted the "fleshy" parts will look pink as can be seen in some of the smaller ones.  They can also blow up much larger than this like an anemone. <<Typical Corallimorph behavior>> The red stuff also appeared when the new rock was put in.  It has now spread over about 40% of this rock.  It is made up of many small -3mm or so lobes.  These lobes are vertically flat. <<The red alga 'may' become problematic/spread more than you like.  If this happens, your best bet for controlling it (short of manual extraction) will be an urchin species.  Mespilia globulus is a good choice for smaller systems or a Diadema species for large (100g +) tanks...but be aware it has been my experience the latter will also sometimes graze on Acroporids.  EricR>>

Where the Red Fern Grows  - 03/24/07 Hey Guys, Absolutely love the site. Have been lurking here for about 6 months now and every question I have had has been answered by doing research on the site. Every one except this one... <Is indeed a great resource and thanks for taking the time for looking before asking now, lets see if we can help..> In the last 6-8 weeks we had this beautiful red fern "thing" grow off of a piece of Live Rock that we obtained from our LFS. In the past 2 weeks the thing has gone gang busta on us. We are not sure if it is ok to have in our aquarium. Could you try to "id" it for us (sending an attached photo) and let us know if it should be removed. I hope it won't need to be removed as I think that is very beautiful. <Not to worry, it looks to me, and without further close-ups, like Gracilaria, a type of red algae that is quite common in aquaria and food markets. It's harmless to your system and I agree, adds a really vivid colour. Although you mention excessive growth, which may be due to high nutrient levels, and I would definitely check your nitrates here> Thanks for all your help. <Pleasure, Olly> Dawn <Also thank you for taking the time to spell and punctuate everything correctly>

Algae ID - Gracilaria textorii? Fauchea? Red Macroalgae   1/30/07 Hello WWW crew! <Hi there!  Mich with you today.> I'm having quite a time ID'ing this algae. I've found pics of Gracilaria textorii that look similar, and pics of Fauchea sp. that look similar. Any looking at the pics of Fauchea and g. textorii, I think THEY look similar to each other! <Heeheeee!> HELP! <Given the choice between the two, my vote goes for Gracilaria textorii, though I am no expert in algae.> To save you pain of email attachments, I've hosted the images I took last night on my website here: http://www.climatestudios.com/algae/algaeid.html <Got it.> Any ideas? <A beautiful red Macroalgae for sure.> Thanks so <You're welcome!  -Mich>
Re: Algae ID - Gracilaria Textorii? Fauchea? Red Macroalgae <Hello again, Mich here.> Thanks for the reply. <You're welcome.> I now have another opinion that thinks Delesseriaceae. <Another possibility.  I don't know if you are aware, but there are nearly 4000 species of saltwater red algae, so narrowing down the exact species is quite a challenge.  A marine botanist would probably be more suited for the task.  I will pass along to WWM guru Bob Fenner for comment.> Links to 2 new pics of leaves: http://www.climatestudios.com/algae/alg_close1.jpg, http://www.climatestudios.com/algae/alg_close2.jpg. Also, if it helps, when this is pulled and left out, there is an almost "stinging" feeling in the air. A couple months ago, I pulled a bunch out and as my girlfriend and I were laying in bed, our eyes stung (both of us) and there was a very strange odor. Since then, I've tossed it outside when removed. Now, as the clump I pulled is drying, there is the same odor, and places on my arms where I touched after handling it are itchy, similar to an allergic reaction. <Yikes!  I'd recommend wearing gloves in the future.> Link to original page: http://www.climatestudios.com/algae/algaeid.html To REEF CENTRAL thread: http://www.reefcentral.com/forums/showthread.php?s=&threadid=1032798 <You're welcome!  -Mich>
RMF any thoughts... <From what I see/saw, this look/ed like a Fauchea species. BobF>

Algae et al. ID, coldwater?   1/14/07 Hi All, Picture 1: Last week I saw some red macroalgae I was interested in and asked what it was, no one knew, the tank was simply marked "Red Macroalgae on rock"  I tried researching it from memory but with no luck.  This past Friday I went there and although the piece I was interested in was gone they had another nice one and I bought it. <Not for a tropical tank I hope> Following are a couple close-ups and one almost full shot. The piece is about 7 inches tall.  In all the research on pictures I saw one that looks similar, Gracilaria textorii. With all the different species of red macroalgae it's difficult for me to really know which one it could be.  The fronds are leathery feeling and one small blade is solid white, as opposed to how Caulerpa seems to turn clear.  My concerns are amount of light, how to trim it down when needed, and water movement.  It came attached to a very tiny rock fragment.    <Can't put my finger on the genus here, maybe a Galaxaura... but am pretty sure this is a cold water organism... collected off of California... not an uncommon practice... some folks who don't know... sell/buy Metridium, Tealia et al. anemones, Catalina Gobies, macrophytes from here... Won't live for long in warm water... Picture 2: A couple weeks ago I asked to purchase a small bit of Chaeto from the LFS and the staff person pulled it from the sump under their soft coral display tank.  Within a couple days I had tons of copepods, but I also noticed this thin red line on my glass and at first I thought it was a worm.  But it is growing and changing.  I have 10 of these 'red things' located in one area growing on the glass.  Attached is a picture of two growths labeled with the dates.  The longest one on Day 1/14 is almost a half inch in length.  Do you have an idea what it might be?      Thank you. Debra Piedra <Mmm, maybe a hydroid... originating from/with the coldwater Rhodophyte. I would keep your eye on the algae... remove it when it appears to be decomposing. Bob Fenner>

Another Rhodophyte? - 08/03/06 Hey, how's it going? <<Fine, thanks>> Can you ID the subject of this picture for me? Thanks. Jim H. <<Appears to me as a translucent species of Rhodophyte.  We've had a couple inquiries on these of late...must have been an influx of live rock from someplace where these are common.  Regards, EricR>>

Saltwater ID   8/1/06 Hello, use your site for reference all the time, thanks!    <Welcome>   I am wondering what this is. I assumed it was algae, but have not been able to ID it anywhere. Though I saw it on your site, but not sure. It is growing rapidly and I would like to either trim it or move it.   Thanks <Is a beautiful photo and specimen of a Rhodophyte... likely a Fauchea species: http://search.msn.com/images/results.aspx?FORM=IRRE&q=fauchea and on WWM: http://wetwebmedia.com/redalgae.htm Can be trimmed, cut, pulled... Thank you for sharing. Bob Fenner>

What is it?  Red algae ID 2/25/04 WWM Crew, I have this probable red algae growing in one of my tanks. Do you know what it is? First picture was taken today. the other picture in Sept. 03. Mitch <Hi Mitch.  I am not sure of the ID of the first algae that sort of looks like a bunch of curlicues.  The second algae that is sort of feathery looking, looks like Gracilaria.  Both are beautiful and nice finds!  Best Regards.  Adam>
Can you identify this algae <Looks like Botryocladia. Please see here: http://www.wetwebmedia.com/redalgfaqs.htm Bob Fenner>

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Marine Aquarium Algae Control

by Robert (Bob) Fenner

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