Re: beard algae

>From: DIONIGI MALADORNO 201-812-3495 <DIONIGI.MALADORNO at roche_com>
>Date: Thu, 23 May 1996 15:56:00 -0500 (EST)
>Subject: Beard Algae
>- - You do not mention allelochemicals  as an additional way (other
>than competition for nutrients) by which  higher plants can overcome
>this type of algae. Is it due to lack of data on this subject, or to
>the fact that you exclude the existence of this mechanism?

This was an oversight! However, I am not aware of any specific data on red
algae. I think the universal idea of allelochemical interactions among _ALL_
plant and algae species is somewhat speculative because of the limited
number of plants and algae studied and due to the specific study or field
conditions involved.  We do know, however, that aquarists have reported that
red algae does not survive when infested plants are introduced into
established densely planted aquaria. Therefore, I would not rule allelopathy
out either <g>. The strategy is still the same.... have a lots of healthy
growing plants and 'optimum' growing conditions... the mechanism is the only
change.... of course with this mechanism, patience must be exercised by teh
aquarist.... it can take a while for the algae to dissappear. 

To support this notion,  I now recall that when I had a badly infested red
algae tank (over 10 years ago <g>), the dominant plants were Cryptocoryne
affinis, Echinodorus bleheri and Anubias barteri var. nana. As we have all
seen , the red algae is attracted to the Anuabias like a magnet. The crypts
are also slow growing, but never got any red algae to attach. The sword
plant put out new leaves almost on a daily basis and soon afterwards they
were covered with fur. While I can't remember red algae on the affinis, I do
have pictures of other crypts with red algae in different tanks. So, it
appears that some plants may have ability to resist and maybe even can
release enough chemicals in a confined space to discourage viability of a
specific alga. (Maybe it can even work in reverse if there is enough algae?)
Certainly chemical poisoning seems to be the case among certain higher
plants. Maybe I should briefly mention this as a possibility? Thanks for the

Anyone else see interesting interaction between certain plants and red algae?

> The
>reason I asked this question is that I had frequently and for long
>periods of time excess Fe and macro- nutrients in my tanks, but no
>beard algae (just tons of cyanobacteria!).

> I wonder if anything like
>a direct inhibitory effect from plants played a role in avoiding
>beard algae infestation.

Or the conditions favorable to bluegreen were less favorable to red algae
(e.g. wrong N to P ratio). Or was there a competition between the two alga.

> I would exclude competition from
>cyanobacteria as well, since now they are gone, and no beard algae
>are visible yet.

Maybe there isn't any red algae in your tank? <g> Or the conditions are now
better so that your plants are sucking up nutrients more quickly... Why
don't you put an red algae infested plant in your tank and test your theory!
Diana Walstad did and she observed that the algae did not spread much, and
then eventually disappeared.

>- - Can you provide recommendations on the living conditions of your
>japanese shrimps? I have located a local dealer that should receive
>them shortly (last time he called them 'Guatemala Shrimps', but they
>looked like C. japonica). I have soft water, and I wonder if this
>could be a problem. Japan is also a temperate zone, and I wonder if
>tropical temperatures throughout the year would be a concern.

I have kept mine in a wide temperature range from low 70's to low 80's and
haven't noticed any problems. Please note that their algae eating
effectiveness depends on their density. Perhaps 1 or more per gallon are needed!
I will be curious about your price. In Japan they cost equivalent of $2 (US). 

>- - Clearly  the concept of 'sterilization' is not the main message
>that comes from your review, but it prompts me to bring up the fact
>that I do not agree with those who consider it as a factor to
>prevent  algae infestations. I used bleach treatment of plants with
>success, but mostly for cosmetic reasons, or in order to give
>individual plants a chance to better recover from algae

Wait until you get Oedogonium <g>

>My point is that I suspect that many algae are almost ubiquitous
>(are we really sure that plants and fish are the main carriers? What
>about air, dust particles and tapwater?),

Tap water is an interesting point! I will have to check our water treatment
about their filtration capability (for spores). Ten - 15 years ago, red
algae was rampant in the Raleigh area!

> and apparently algae-free
>tanks do carry small amounts of algae. They may however become
>visibly infested if the conditions change in favor of algae, even
>without any introduction of new plants or new fish. For example, I
>have a 20 gal tank with good plant growth and a quite heavy fish
>load. No visible algae problems. I have two small box filters on
>this tank. Suddenly, a couple months ago, I noticed a bloom of
>cyanobacteria everywhere, associated with a previously unseen growth
>of beard algae on some plants only. No new fish or plants had been
>introduced. However, after a while I realized that one of the two
>filters was not functioning, with a  reduction of biological
>filtration. Once the filter was fixed and the most severely affected
>plants removed, the whole tank recovered promptly.  

This periodic appearance of BG is very common.

>Conversely, an algae infested plant introduced in a tank with
>unfavorable environment for algae should recover without spreading
>the problem.  I say "should" because I have much less experience
>than other people on this list, and I have not really tested this
>hypothesis. I am curious to see if other people have hypotheses or
>facts that contradict my thoughts.

It is easy to test. Give it a try! But have some siamensis on hand <g>.

>- - I have soft water (~5 DH, ~3KH, pH ~6.5), and almost never see
>beard algae despite high CO2 levels. I wonder if this is in
>contraddiction with what you wrote in the section on CO2, or if
>other factors explain it.

I thought I addressed the apparent contradition of high CO2 and no red
algae. (i.e. fast growing healthy plants fueled even more by higher CO2!)

Thanks for the thoughtful feedback. I was hoping someone would respond!!! 

Neil Frank, TAG editor    Aquatic Gardeners Association    Raleigh, NC USA