Chaetomorpha question 11/10/04
In Today's Q/A there was mention of Chaetomorpha and to allow it to roll around. Is this a part of the requirements for successful growth of this plant?  <Chaetomorpha does not root and does best when it is not allowed to simply lay on the bottom of the tank, but it is very forgiving.  I have successfully grown it without keeping it suspended.  IME, the most important thing is to thin it often and not allow it to become too dense. HTH.  Adam

Halimeda getting white - going sexual 3/11/04
Hello Anthony!
<cheers, Thanassis>
In my display tank, as well as in my sump, I have macroalgae growing (Dictyota, Halimeda and  a little Caulerpa racemosa).
<please do resist mixing macroalgae species... they will not fare well together in the long run (competition and chemical aggression)>
During the last couple of days I noticed that some -not all- of my Halimeda has turned white - I mean totally white colour. Does this mean it is dead?
<sort of... it may simply have gone sexual and new growth will sprout in the system in the next couple of months. Else, it has suffered from the very toxic/noxious Caulerpa racemosa (one of the most noxious of all macros in the sea)>
If yes, should I remove it from the tank?
<you can let it dissolve and provide calcium. Also do a large water change>
I checked my Ca Hardness is 11 dKH and Ca is 450. What could be the reason of this problem?
<no problem at all here>
Thanks, Thanassis
<best regards, Anthony>

Chaetomorpha
Hi,
I have just started a 10 gal refugium for my 26 gal reef tank. Tank has been set up about a year. I have ordered two different batches of Chaetomorpha and both have done the same thing. When I first get it it's light green in color and soft after about 1 to 2 weeks it turns dark green and gets really stiff. << That sound normal. >> It doesn't look like it is growing at all.
I have an 18 watt florescent light on it running 24 hours. Any idea on what I could do to make it grow or may be doing wrong? << That doesn't sound like much light.  I would try at least 30 watts of compact lighting, and I would like the refugium for about 12 hours per day. >> Or does it take a while to start growing? << Well it is certainly not a fast growing algae.  And that isn't bad. Remember it can only grow as fast as the nutrients allow it to. So if you have a big skimmer in there, and you don't feed your tank, it won't grow. >> The Chaeto has been in there now for about a month and a half with no growth. One other question if it does start growing is it better to cut pieces off or just pull pieces off. << Good question.  It is better to pinch it off.  By this I mean you pinch it between your fingers first, then cut it off.  That way, the pinching helps prevent the alga from "bleeding" when you cut it. >>
Thanks for any help you can give.   
<<  Adam Blundell  >>

Halimeda gone sexual 6/3/03
Good morning:
<Howdy>
Overnight my Halimeda seems to have been attacked by red and green spots (in the terrestrial world I would call them spider mites) turning the plants white and the water has gone cloudy.
<what has happened is that they have gone from being vegetative... either from a stress (newly acquired, or recently stress from a temperature or salinity change, e.g.)... or from a period of vigorous growth without adequate pruning which has allowed the colony to go sexual/mature>
No fish currently in residence as they are in ick quarantine but my polyps remain as do the crabs, snails and LR. Should I be ripping the Halimedas out of there and what could be attacking them?
<the bleached colonies are dead. New colonies are likely to sprout in the tank within months. Remove the dead matter and conduct a large water change. Use fresh carbon too>
Thanks as always for your assistance. Charlie
<kind regards, Anthony>

Green seaweed research questions (and useful, scientific input!)
Hi Bob,
I found your address at the WetWeb site and thought I'd contact you directly. Hope you don't mind.
<Not at all>
I'm a bio professor/researcher who studies the reproductive behavior of tropical green algae in their natural environments (Halimeda, Caulerpa, Penicillus, etc). I notice a fair number of posts to aquarium sites that have to do with "green clouds", "white" or "dying seaweeds",
etc. and recognize (as you do) that most of this relates to the sexual reproduction of these seaweeds... a 24 hour conversion from sterile to fertile condition, followed by explosive gamete release at dawn and immediate death of the "parent".
<Yes.>
My research explores the consequences of these reproductive events on coral reefs (mostly Caribbean, though I'm currently on sabbatical in Guam). I'm particularly interested in what induces a seaweed to become fertile, since we often find hundred to thousands of algae on a reef (but
never all of them) becoming simultaneously fertile... not only is the ensuing bout of sex the next morning a spectacular visual phenomenon..
the subsequent death of so many "adult" seaweeds has important ecological implications for the reef community as a whole.
<Agreed>
I notice from various posts within the aquarium trade that lights, chemistry, temperature, stress, etc, etc, are implicated in the onset or prevention of reproduction by green seaweeds in aquaria. Do you know of any formal treatment of this idea... 
<No... unfortunately seem to be entirely anecdotal accounts... of "stress", change that bring on these events.>
or is it just a hodgepodge of observations thrown out over time? I notice you reference "24 h" lighting as a preventative and I've seen reference to blue lights, or
non-blue lights (can't remember which) having similar effects. If you're interested, I'd love to pick your brain about this... or you can sic me on someone else.
<Very glad to be of assistance.>
If interested, you can also learn more about my research on seaweeds by visiting: http://lclark.edu/~clifton/Algae.html
<Thank you much for this reference. Will post to our sites (WetWebMedia) for hobbyist perusal>
Thanks for your time... I hope to hear back from you.
Ken Clifton
<Sorry for the delay in response. Have been on a liveaboard... in the Bahamas. Be chatting, Bob Fenner>

Culturing Halimeda
Dear Bob, Steve, or Anthony:
<Anthony and at least two of my personalities here...Bob and Steve unavailable>
I emailed you a couple of days ago regarding reducing the sand bed depth in my 150gal FOWLR system. I have already began the reduction and am pleased to report everything seems ok! Thanks for the good advice!
<ducky...just ducky>
I was wondering if I could pick your brain on one other item. I have a nice stand of Halimeda on one side of the tank, and I was wondering if it is possible to propagate this macroalgae by "cuttings".
<not so literally, although reproduces sexually with ease once mature. best bets are rooting in sand>
Or- is there a better way? If Halimeda can be propagated in this manner, do the "cuttings" need to be secured to a rock or other substrate in order to grow?
<see above... although better to let it mature and reproduce naturally. A sexual event is indicated by a sudden "bleaching" of the colony leaving behind a bespeckled (with green) white plant that soon dissolves. "Babies" pop up everywhere afterwards within weeks to months. Skim well during the event>
I'd appreciate any tips/comments/warnings you might have on propagating this macroalgae.
<of course...you could always try good wine and Luther Vandross music>
Thanks! Scott F
<you are quite welcome. Anthony>

Halimeda Cycle
Oh Wise Guys! <<and hello to you.>>
I had an interesting occurrence this past weekend that I'd like to
understand. I have a lot of Halimeda in my 100gal tank and about half of it went into the end of its life bloom (my poor term). You know, at first it turns white with tiny green spots or spores on the outer most leaves, then it releases these about a day later into the water causing a very cloudy condition. The interesting part was not the bloom - as I've seen it before - but the apparent suffering caused to one of two yellow-tailed blue damsels.
For a day or two he showed signs of poor water chemistry. He was hiding, not eating or seen resting on the bottom. I immediately did a 5 gal water change. Then followed it up a day later with another 5 gallons. The fish seemed to recover quickly. What caused the stress? The Foxface, cinnamon clown, and yellow tang were also unaffected as was the red brain coral. <<Very hard to say specifically without some chemical analysis. Did you check any of the normal parameters... perhaps nitrates skyrocketed... hard to state at this point what the problem was exactly besides the obvious: something from the algae bloom/die-off.>>
P.S. If I were to add one more way cool fish what would you suggest?
<<Oh... the list is too long. Do check through the pages in WetWebMedia. Many, many to choose from.>>
P.P.S. Finally bought Mr. Fenner's book at Scripps Aquarium here locally. Boy, I didn't expect so many beautiful photos. It can be a 'coffee table' book as well as a good reference. <<Indeed.>> Also, what happened to the Rabbitfishes (Foxface) section? <<If you look in WetWebMedia, you'll see these fish covered in the same section as the Tang/Surgeonfish.>>
David
<<Cheers, J -- >>