> From: Arthur Johansen <johansen at soback_kornet.nm.kr>
> Date: Sat, 21 Sep 1996 05:41:15 +0900
> Subject: Algae questions
> To all you algae experts out there,
> I have been reading this list for a while and don't remember if anyone
> has discussed this before.  It also seems to me that the FAQ assumed 
> algae was bad and needed to be gotten rid of.
> Is there some particular reason why we
> shouldn't allow algae to grow in our fish/plant tanks?  Do the reasons
> differ depending on what type of fish/plants you have?  Or do they differ
> depending on what type of algae is growing?  Is the main
> reason purely aesthetics?  Doesn't some algae help the fish/plants to
> be more healthy?

There is ALWAYS going to be some algae in a tank.  The trick is to keep it
under control.  For instance, in my Julidichromis tank, which has no
plants, I let the algae grow wild and free.  Over on the other side of the
apartment, I have a tank with lower light levels and no plants either... 
this tank tends to get choked with blue-green algae, which is good in
small quantities (consumes nitrogen) but in large quantities can produce
an ugly carpet covering everything, and chokes out oxygen as a thick film
on the surface.  Then over in the big heavily-planted tank, I always am
aware of the danger of unbalanced algae which can kill all the plants by
suffocating them, cover the entire tank in furry brush (which is not
esthetically pleasing), as well as the aforementioned blue-green algae
carpet (which, ironically is happening right now.  Something needs to be

Actually, the FAQ does a pretty nice job of laying it out right from the
first two paragraphs, telling you algae may be desireable:

"There are two categories of algae of concern to aquarists: "good" and
"bad". Good algae is present in small quantities, is indicative of good
water quality and is easily kept in check by algae eating fish or simple
removal during routine maintenance.  This algae is a natural consequence
of having a container of water with nutrients and a light source.

Bad algae is either an indicator of bad water quality or is a type of
algae that tends to overtake the tank and ruin the aesthetics the aquarist
is trying to achieve. The label of "bad" is entirely subjective. For
example, one type of green, hair-like algae is considered a plague by some
American aquarists, yet is cultivated by European aquarists as a valuable
addition to most tanks, serving as a dietary supplement for the fish." 

  - Erik

Erik D. Olson					         amazingly, at home
eriko at wrq_com