FAQs about Green Macro-Algae Identification
Related Articles: Embracing Biodiversity, Green
Algae By Mark E. Evans, Green
Algae, Avoiding Algae
Problems in Marine System, Algae
Control, Marine Maintenance,
Nutrient Control and Export,
Marine Scavengers, Snails, Hermit
Green Crabs, Sea Urchins, Blennies, Algae
Filters, Ctenochaetus/Bristle Mouth
Tangs, Zebrasoma/Sailfin Tangs,
Skimmers, Skimmer Selection, Marine Algae, Coralline Algae, Green Algae, Brown
"Algae"/(Cyanobacteria), Diatoms, Brown
Related FAQs: Green
Macro-Algae ID 1, Green
Macro-Algae ID 2, Green Macro-Algae
ID 3, Green Macro-Algae ID 4,
Green Macro Algae ID
6, Green Macro Algae ID 7,
Green Macro Algae ID 8, &
Caulerpas, Green Macro-Algae 1, Green Macro-Algae 2, Green Macro-Algae 3, Green Macro-Algae 4, Chlorophyte Behavior, Chlorophyte Compatibility/Control,
Chlorophyte Selection, Chlorophyte Systems, Chlorophyte Nutrition, Chlorophyte Disease, Chlorophyte Reproduction/Propagation,
Marine Algae ID 1, Marine Algae ID 2, Marine Algae Control FAQs II, Marine Algaecide Use, Nutrient Limitation, Marine Algae Eaters, Culturing Macro-Algae; Controlling: BGA/Cyano, Red/Encrusting Algae, Green Algae, Brown/Diatom Algae,
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Marine Aquarium Algae Control
by Robert (Bob) Fenner
Algae.... ID 9/1/15
<WHY are you sending us 4 megs of uncropped pix?>
I'm at a loss could you please id this algae, I hope it's not what I think it
<.... might not be an algae. HAVE you read on WWM re Identification?
Perhaps Derbesia, Bryopsis.... maybe a Hydrozoan. READ; don't write. Bob Fenner>
Hair Algae? Making Me Crazy/Algae Control/Jack Daniels
If You Please 2/4/10
I know you here it over and over but all of you are awesome.
I have never seen a sight with so much information and so
helpful. I use your sight constantly. I started my first
saltwater tank in May and now have 3 tanks.
My daughter and girlfriend and I love learning and caring for all
of our new friends. The tank I need help with is our oldest one
(only 9 months). It is a reef tank, 75 gallons with a 30 gallon
sump. We have 4 actinics, 2 halides and at least 100 lbs of live
rock. I check chemicals at least twice a week and always top off
with RO. Ammonia and nitrite are always zero, pH is generally
8.4, alkalinity 8-9, CA 400-440 and temp 79-82. I battle nitrate
now and then but in general it is around 5 almost never above 20.
The tank has been pristine (I am probably one of the keepers you
talk about that can't stop messing with the tank) but I am
now waging war against some type of hair algae, I think. It grows
rapidly on any live rock that has light exposure that doesn't
already have a coral or anything living on it. I
have checked phosphate repeatedly but the test kit I have is very
hard to tell color difference on.
<Yes, generally phosphate is absorbed by algae as soon as it
forms. You likely wouldn't get a reading unless it was
forming faster than the algae can absorb it.>
It seems like it is always at the lowest color. Yesterday I added
a phosphate reactor and Phosban to the system. Whatever it is it
creates a mat of brown particles that form in a mat over
everything. It is concentrated more on the fibers of the algae
though. I use a bulb syringe daily to break the mat apart and
clean the rock.
<Mmm, go here, look anything similar to the pics? http://www.wetwebmedia.com/bluegralgae.htm>
The filtration removes them to the first particle filter which I
change. In 24 hours it is all back and the hair gets longer. I
looked at the brown seed like particles that form the mat under a
microscope and they appear to move. It is green and brown and has
what appears to be eye like spots. Is this algae or some type of
worm and is it related to the hair or two separate issues?
<May be pods of some type.>
It is making me crazy and ruins the appearance of the tank.
Will the phosphate reactor solve the problem?
<Unlikely, a protein skimmer would do more for you here than
anything else. You do not mention the use of one so I'll
assume you do not have one. It appears you have excess nutrients
in the water and with the presence of good
lighting as you have will accelerate the growth. Steps to
eliminate/control the problem can be found in the links
I have attached a photo of the algae. You can see the brown green
particles on the left under the clam in the algae.
<Not really resolved enough for me to see any detail, but it
appears to be nuisance algae.>
The algae is dark green with a bluish streak at the center of the
filament. I have read tons of your articles and Bobs book on
invertebrates. I can't find anything that specifically
addresses my issue. Help!
<See/read all related info contained in the links above and
implement the advice. This problem is not going to go away
overnight, as it didn't start overnight. It will take time
and patience. James (Salty Dog)>
<<Mmm, no... this is a Chlorophyte... Likely Bryopsis. Read
and the linked files above. RMF>>
Re Hair Algae? Making Me Crazy/Algae Control/Jack
Daniels If You Please 2/5/10
Wow you guys are amazing. Super fast response.
This is the picture on the FAQ you sent me that looks most like
what I have.
Here is another photo from my tank. Sorry couldn't get a
Is this Bryopsis or Derbesia. I couldn't tell from the
<Yours or the FAQ picture? Mr. Fenner believes what you have
Read FAQ's here for help/advice.
Are the pods what new hair is growing from?
<No, and it was just a suggestion. Without actually seeing
it/them makes it nearly impossible to ID.>
Should I continue the attack on them?
<On the algae, yes, implement what you have read and read
OK so a few more facts for you and then what I think my game plan
should be. If you could just tell me if I am on the right path
that would be great.
I do run a Super Skimmer. It produces about 3 inches of Skimmate
<Cleaning the riser/reaction chamber every couple of days will
increase efficiency of the skimmer.>
I also use a UV sterilizer that dumps into carbon media.
I have a Sohal, a Kohle <Kole>, two Percula Clowns,
Foxface, Bicolor Pygmy Angel and a Niger Triggerfish. All are
small less than two and half inches. I also have 3 shrimp and a
Tridacna. Corals are Pulsing Xenia (over taking the tank)
Frogspawn, various mushrooms and elephant ear.
<Too much load for this system which in turn promotes excess
nutrients, and most of your fish will need larger quarters in the
I feed once a day 1 cube of Formula 2 and one cube of Formula B.
I used to feed twice but have been trying to limit nutrients for
over two months.
Should I feed less? They devour it in 2 minutes and still seem
hungry. I am worried they aren't getting enough.
<I wouldn't feed two cubes at once. Spread it out over
three daily feedings.>
Should I switch them to flakes? Is this less nutrient input?
<Would be less nutritional. Frozen foods will generally
produce more waste in the water unless rinsed in a net prior to
feeding. You might give the New Life Spectrum Pellets a try. A
very nutritional food with little waste, is all I feed.>
Rest of my plan, yes or no?
Switch out my actinics -- 9 months old.
<I would not use this lighting for now, especially with four
of them in a 75 gallon tank. Actinic lighting peaks in the mid
400nm range and can promote algae growth. There is enough blue
present in your MH lamps to promote
photosynthesis for other light loving animals. If anything, cut
it down to one or two actinics.>
Do I need to switch the halide bulbs also?
<I don't know, they are generally effective in the rated
Kelvin temperature for a year.>
Decrease halide time from 8 hours to 6. (actinics run 12)
<Halides are fine, I'd decrease the actinic photoperiod to
a couple of hours before the halides come on and turn back on for
a couple of hours just before the halides turn off.
Remove the rock -- again! And scrub in RO.
<No, do not do this, you will be killing other life present in
Continue to blow off the pods daily with a bulb syringe.
What about raising the light unit higher? It is about 8 inches
above the tank now.
Continue to use the phosphate reactor.
<Might as well, you bought it.>
Is this enough or should also try the pH increase and the ferric
<????. PhosBan is a synthetic ferric oxide.
Leave pH alone and read/act where you were sent.>
Again thank you!
<You're welcome. James (Salty Dog)>
|Re Hair Algae? Making Me Crazy/Algae
Control/Jack Daniels If You Please 2/5/10
<You're welcome, Chris.>
Are you guys funded by sponsors, donations or both?
<A little of both, and I believe some may come out of Bob's
wallet. What say you, Bob? We are strictly a non-profit
organization, the crew's time is donated, no paychecks given
<<Not money from me, but perhaps its equivalent, time,
effort. Most of the incoming monies are from commercial sponsors
who believe in what we do (educating, inspiring their present,
future customer base); and most outgoing is for content;
principally our on-line 'zine. RMF>>
I would like to contribute to your cause if you are donation
<Great, and will be appreciated. Go to this link, scroll down to
the bottom of the page where you will
see a donate tab.
James (Salty Dog)>
Algae identification... Reading --
I've seen my share of algae come and go in my tank, and most
recently killed off a good bit of Bryopsis by elevating my
alkalinity. Now there is just one little tuft of what I suppose
is just hair algae (though no crabs,
snails, tangs or coral beauty will eat it), and some really funky
stuff that I haven't seen a picture of anywhere. I tried to
take a picture with my phone, but as you can see, the picture is
almost worthless. I'll do my best
<Need a better camera, pic...>
First, this stuff is very slow growing. The "flesh" is
very tough...almost reminds me of a cactus. There are no leaves
or stems anywhere. There are little knobby protrusions all over
this mound, that is about the size of a ping pong ball (there are
a few other small colonies starting to grow elsewhere in the
tank...hence the question). There also seems to be some white,
almost cottony stuff attached to the mound, which you can sort of
make out in the picture.
Would you guys be able to venture a guess as to what I have on my
hands and what the recommended course of action would be? Thanks
so much for your time and effort, it is truly appreciated.
<Please read here:
Scroll down to the tray on Marine Algae... see the sections re
Green/Chlorophyte Algae ID, Control. Bob Fenner>
Re: algae identification
Thanks so much for the reply and for pointing me in the
I did find a picture of the algae in question.
You had suggested either Bryopsis or Derbesia, but this is
definitely not the case. This stuff is not leafy or
filamentous. I have included the picture I just found, and
the original post below.
<I see this>
Other than that small tuft of hair algae I mentioned
previously, and coralline, there is no other visible algae
growth in the tank, and I am running both Purigen and
The description below seems pretty accurate to me. I'm
sorry to take up your valuable time by pressing this issue,
but thought some more info might shed some more light on
Here is what the previous submission said...
"*Saltwater Question, grn alg. ID 4/8/07
*Hey Wet Web Crew,
I have a question regarding something that has just
"popped up" in our tank. We have a 125 gallon
saltwater tank, and this green algae looking plant started
growing at an enormous rate. It has a round structure with
"blebs" that branch out, kind of reminds me of
melted wax. Currently there are two on the same rock, one
is about the size of an egg and the other the size of a
golf ball. I have looked all over, but have not found
anything that looks like this. Is this something that we
should take out or leave alone?
<Likely want to address... along with the evident BGA
(the red mat.)... as very likely a matter of excess
nutrient... secondarily a lack of competition,
I have embedded the image so you do not have to
<Better to attach...>
however if that does not work, there is an attached file as
<Do take a look on the Net re the genera Derbesia and
Bryopsis... and onto WWM re Marine Algae, Control... can be
controlled indirectly... as you will see.
and the linked files above...
Bob Fenner> "
Again, thanks so much for all you do Mr. Fenner!
<And you for sharing. BobF>
|Re: algae identification
After finding that picture, I got on the right track and have
determined this to be a species of Codium. I've now read
that this is a fairly rare and prized macro algae? Is there
anything special I should do / not do
with this stuff?
Thanks again so much for your help!
<Perhaps culture it, offer it for sale, sell it to/through
the Net, your LFS... B>
Mystery Algae/Algae ID 9/5/09
Well, I do not thing this is Turtleweed or maidens hair (not
straight enough) Any thoughts? it is very stiff and likes to
attach to rocks and does not grow to terribly fast.
Just curious and thanks!
<Yes, what you have is a specie of Chaetomorpha, Spaghetti
Algae, a good algae for refugiums,
but can be problematic if left in the main display, spreads
quickly and can overtake your live rock.
James (Salty Dog)>
Re Mystery Algae/Algae ID
I have 2 species of Chaeto, and this is not at all curly but
stiffer and the "blades," if you will, are straight and
split at the top.
And like I said it does not grow fast at all. Macro algaes grow
fast and this does not, making me think it is more plant like.
Any other thoughts? I can send a more detailed picture if you
need it. :).
<Mr. Fenner also had his doubts that this may not be Chaeto.
Problem here in indentifying is that there are literally hundreds
of species of algae.
<<About thirty thousand>>
Years ago I had a very similar clump of algae that my LFS
identified as Chaeto. Perhaps a more detailed photo (and do
increase the brightness) may lead to a more positive ID of the
Thanks for your help. :)
<You're welcome. James (Salty Dog)>
Sent from my iPod
<Sent from my outdated laptop.>
<<RMF thinks this may be a species of Derbesia>>
Algae ID Query -- 09/08/09
Received a couple more pics from the querior and it sure looks
like green Gracilaria to me.
See attachment photo of green Gracilaria.
<May be. B>
Re Mystery Algae/Algae ID 9/8/09
LOL! I like your "sent from my outdated laptop!" that
hehe. I agree with Bob, since one characteristic of this, lets
say "plant," is that is that Chaeto does not seem to
ROOT to rock, at least none of mine did.
Okay, are more pics. I hope it helps. :)
<I've did some searching/comparing, and I'm guessing
this is a species of green Gracilaria algae. See attached photo I
compared to. James (Salty Dog)>
Re Mystery Algae/Algae ID 9/8/09
I saw that picture on your web site, but it was so faded and
blurry I didn't really assume that was it. I sent several
more pictures. You are WELCOME to use any of them to replace the
picture you have if you wish. :)
<Will pass on to Bob, thank you.>
Thanks and I will wait to get a confirmation on that. I have
found this grows fine in MANY different lighting levels. I have
t-5s and it grows at the top and bottom. It is hardy and I think
MUCH more attractive than Chaeto and doesn't get all stuck up
in the pumps like Chaeto.
Maybe I should aquaculture and sell this stuff! lol! My Coral
Beauty Angel does not touch it, though it has slowly eaten all
the actual Chaeto in the system. Funny, i didn't want a tang
to eat all my macro algae.... so I got a dwarf angel.... DERR!!
lol! I never had one before, so I didn't even THINK about it
eating that! It also does not seem to eat the Caulerpa I
have..... the kind that looks like a saw that has blades on each
<You're welcome. James (Salty Dog)>
|Re Mystery Algae/Algae ID
No this definitely NOT it.
Mine is a stiff and like I said before, straight rooting bush like
plant. Gracilaria is soft to the touch and
curly. I have had ago and many others in the past as well. This
stuff is stiff and does not like to bend. Plus in my close up that
I wonder if you got, notice that the shaft is not continuous or
smooth from the top down but more like that like that stiff wild
grass you find in fields.
<Did get the photos.>
I am thinking more that it is a grass of some sort. Plus Gracilaria
does not tend to root quickly like this one does. It is much
hardier that Gracilaria too IMO. And again if the angel is not
eating it (if it was Gracilaria it would) I would also say it may
not be an algae at all.
Again the closest I came to was that Derby stuff you mentioned. I
have had possibly every other macro algae at one time or another so
I know what the popular ones are. I am not a newbie :)
<It is obvious you are not.>
so this question may not be so simple. I guess this remains a
Maybe show my recent pictures to Mr Fenner.
<Mr. Fenner looks at every query/pic before posting and will
inject his thoughts if necessary.>
<<Tis so. RMF>>
My daughter has an underwater camera I may try.
<Additional photos will not help.>
Also I will send a piece if you give me an address.
I GOTSTA KNOW!!! LOL
<Carrie, we just do not have the time to do in depth
identification queries that would require much more time than we
can devote on a daily basis, as each crew members time spent is
likely no more than an hour per day. I would suggest that you post
this question on one or more of the marine bulletin boards. You may
also want to search this site by going here.
And tons of Derbesia photos here for comparison.
Hoping this helps you out. James (Salty Dog)>
small green algae in newer tank, SW, ID sans pix --
Thanks in advance for the help, and the site in general. It has been a
huge resource to me as I am starting up my first reef tank.
The tank has been up and running for about a month now. Thanks to your
site, I found that I first
experienced diatom algae, then had a small bout of Cyanobacteria and
now that is fading and I am starting to see a small green type of algae
growing on the glass.
It is not a slime or a hair, but looks more like a bunch of little
green "y"s reaching towards the inside of the tank. I
apologize for not supplying a picture, but I couldn't get mine to
focus that close. Just wondering if you had an idea of what specific
kind of algae it is and how much it should concern me. I couldn't
find an ID that matched this .. I did try!
<Mmm, not able to tell with your description here. Please keep
reading, and do send along some well-resolved images when you can. Bob
Green Macro Algae ID: Likely Bryopsis --
I tried looking through your algae files and didn't see
anything similar to this.
<Mmmm, that looks a lot like Bryopsis -- possibly Bryopsis
hypnoides. Please see the photos at the following links for
This is growing in the back corner of my 65 gallon reef tank. I
have 2 peppermint and 1 skunk shrimp, and a bunch of snails.
Should I let this be or try and remove it?
<I'd get every little scrap of it out of there. Bryopsis
can take off, especially in a nutrient rich environment, and be a
real pain to get rid of.>
Unfortunately, I don't have anything in my tank that would
eat it and could you recommend something (fish or otherwise) that
<Optimally, the first step here would be to confirm that what
you have really is Bryopsis or something else entirely, like
Caulerpa, Derbesia, etc. In the case of Bryopsis hypnoides,
unfortunately I don't know of any animals that feed
exclusively on it, but there are some that might. They include
Diadema savignyi (aka: the Long-Spined urchin),
Foxface/Rabbitfish (Siganus spp.), certain Cowries (such as
Cypraea moneta -- aka the 'Money Cowry'), Sacoglossan sea
slugs, and maybe a Sea Hare. I'm not big on recommending sea
slugs and the like because of their specialized diets. One slug
may eat Bryopsis, but it may not eat the particular species that
you want to get rid of. Beyond that, if it does eat it, once the
food source disappears, the slug starves to death. Personally, I
think they're better left in the wild unless you're able
to provide for them long term. Same goes for any potential
livestock. Please see the following link for more information
regarding Bryopsis control with sea slugs - and associated
It's not a problem now which is why I'm asking before it
<Good thinking! Right now, I'd recommend manual removal
(extract any and all clumps, strands, etc), limit the algae's
food source (exercise good nutrient control), and if possible,
introduce a favorable macro algae within a sump/refugium in order
to outcompete the less favorable, invasive species. Bryopsis is a
common nuisance algae in marine systems so as you can imagine,
there's quite a bit of information available on the 'net
regarding its control. Thankfully, you can start right here at
Other links within WWM:
Thanks for all your great informational assistance.
<You're very welcome and good luck! LynnZ>
Re: Neglected tank, algae run a muck
1/4/09 I have been looking on your web site all day, and
found a wealth of information, however, not quite what I am
looking for. I have a 75 gallon reef with a good amount of live
rock. It has been set up for 5 or 6 years. I went through a
period when I didn't take care of it the way I should have
and I have an algae problem. I also have a 20 gallon refugium
with Caulerpa, and I can't remember what the other stuff is
in there. I think it is Chaeto. <Most likely Chaeto if it
looks like green spaghetti. Do be careful with the Caulerpa
though. It's one nasty bugger if it goes sexual on you or
gets in your main display. Here's some information to ID if
you have time http://www.sccat.net/#identification-1e86f5> I
have some hair algae in the refugium also, but that is not may
main concern. In the display tank there is a brush like growth
that I think is Chlorodesmis, based on the pictures I can find.
<A picture would be best to see here, but I have doubts that
you are dealing with Chlorodesmis aka maidens hair algae.> I
have read that it is a difficult algae to grow, so I am not sure
that is it. It will grow Large clumps in my display tank. I have
tried to manually remove as much as I can, and have started
keeping the tank better, keeping the water quality up, cleaning,
watching the chemistry. But the algae seems to still grow
abundantly. It grows so thick that it traps solid waste near the
rock it grows on and acts like "potting soil". The only
think I am not totally sure about is the phosphate level. I have
trouble distinguishing the color on the test kits. The other
levels test 0 for ammonia nitrate and nitrite. I know from other
articles that there could still be some level in the tank, but it
gets used quickly enough so it doesn't show up on a test. I
am wondering it there is something I can put in the tank to
control this stuff. I have a candy coral that I had to separate
into smaller pieces to remove some on the algae that was killing
a portion of the coral. Thanks for any input you can give me.
<Again, without a picture it is hard to say, but if it looks
like maidens hair, I would think it is probably Bryopsis or hair
algae. Bryopsis can look like ferns or more like hair algae with
tiny hairs growing off the central hair shaft. Its very hard to
get rid of. There are a few things you can do if it is Bryopsis.
I've heard of a few things that work most of the time, and
only one that works all of the time. Ruby lettuce Nudi's will
eat it all, but then you must take care that they don't
starve and either return them to the local fish store or pass
them along to someone else in town who has an algae problem. You
must also be careful of powerheads because they will enter them
and get ripped apart. I've also heard that raising magnesium
works, but it is hit or miss. You can find some more information
on the subject here: Algae control in general
http://www.wetwebmedia.com/algaeconMar.htm Specifics on Bryopsis
|re: Hey Crew 1/4/09 Here are a
couple of pictures to help with ID. I don't see anything that
looks remotely like something coming off the main shaft. Kelley
<Mmm, looks like Bryopsis sp. to me... a tough Green algae to
control... See the Net, WWM re probable approaches. Bob
New Print and
eBook on Amazon
Marine Aquarium Algae Control
by Robert (Bob) Fenner