Related FAQs: Phytoplankton, Algae as Food, Marine Plankton, 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,
Keeping Planktivores Fed
by Bob Fenner,
Coralline Algae, Green Algae, Caulerpas, Coralline Marine Algae, Red Algae in General,
Brown Algae, Blue-Green
"Algae"/(Cyanobacteria), Diatoms, To Pest
Algae/Control , Algae Filters
/A Diversity of Aquatic
Phytoplankton: Use in Marine Aquariums
|by Sara Mavinkurve
Help , gear is definitely available
What is phytoplankton?
"Phytoplankton" is a term that covers a broad group of
autotrophic micro-organisms. Though not usually included in the
aquarist's concept of phytoplankton, diatoms and dinoflagellates
are also types of phytoplankton. The types of phytoplankton commonly
used in aquarium feeding products are Chaetoceros, Nannochloropsis,
Tetraselmis and Isocrysis species (among others).
These are commonly used in aquarium feeding likely because they are
easy to culture and thought to be of the approximate size best for the
organisms we want to feed with them.
3 Sources of Phytoplankton (for aquarists):
1) Phytoplankton in Your Tank:
Some phytoplankton is actually already in your system. In fact, when
you wipe your glass clean with a sponge or Magfloat, and you see green
clouds of green or brown released from the glass--that's
phytoplankton (along with bacteria films, pods and other coral/invert
2) Culturing Phytoplankton at Home:
Phytoplankton can also be cultured at home. In my opinion, unless you
need a very "pure" (containing only one particular species of
phytoplankton) culture, culturing at home is not quite as difficult or
cumbersome as it's rumored to be. I've done so on a windowsill
in a simple 2.5 gallon tank with an airstone. I simply used DT's to
start (which is a mix of phytoplankton
species). The resulting culture was likely only one of these species
(when a mix is used to start a culture, one will almost always out
compete the others). My culture was also likely populated with
bacterias and other microbes. But for my purposes, this was just fine
(if not a good thing). All you really need to culture your own
phytoplankton is a dedicated tank (or other water holding container),
airstone, light source, and "food"/fertilizer for the algae.
(Note: For more step-by-step instructions: Melev's article on
3) Store Bought Phytoplankton:
There are many different types and brands of phytoplankton products
sold online and aquarium stores. They differ in concentration, mix of
species and the form in which they are stored/distributed (i.e. frozen,
refrigerated, spray-dried, etc). Phytoplankton
won't survive in the freezer, nor will it survive at room
temperature. Most will not survive under refrigeration.
However, there are a few species that will. The freezer is too
cold. At room temperature, the algae would need light and air to
survive. However, in the refrigerator, a few species of
phytoplankton can go into a kind of "dormant" state, which
allows them to survive with little air or light.
|"Live" Refrigerated Phytoplankton Controversy
When it comes to refrigerated phytoplankton products, not all
are created equal. This subject is highly
"controversial" in the reef aquarium hobby.
Regardless, I'll dare to say that, based on my
knowledge/experience, I don't believe that all are quite as
entirely live as they claim to be. That's not to say
that all the cells are dead. These products might all have
some live cells. It's simply that some contain species
that are not of those known to survive under refrigeration.
I believe that, of the refrigerated phytoplankton products sold
as "live," DT's phytoplankton (when properly kept
and stored) is likely the highest quality (most live
cells). Personally, it's the only one from which
I'd try to start my own culture. That said, the other
refrigerated products, which likely contain fewer live cells, are
not bad and can certainly be used for many of the same
applications. In fact, for some applications, they might be
better. As with most aquarium products, ultimately,
it's best to judge for yourself (try different products and
see what works best in your system).
Frozen and spray-dried phytoplankton products are certainly dead
phytoplankton cells. Again, that doesn't mean they are
useless. For spray-dried phytoplankton, you'll want to soak
the dry phytoplankton first. If you don't, it will float (and
likely get sucked down an overflow). While live phytoplankton is
generally better and will feed more organisms more effectively, frozen
and spray-dried phytoplankton still has its uses. Chances are, at
least some critters in the aquarium will eat it. It can also be
used to feed/raise brine shrimp, rotifers, etc.
Reasons to feed phytoplankton:
There are a few aquarium corals which feed on phytoplankton. The most
common ones are Dendronephtya and ahermatypic (lacking
zooxanthelle) Gorgonians. It's quite possible/likely that other
ahermatypic, azooxanthelle corals also feed on phytoplankton, but the
Dendronephtya and ahermatypic (lacking zooxanthelle)
Gorgonians absolutely need phytoplankton.
Most the corals we keep in aquariums are Hermatypic (both autotrophic
and heterotrophic). This is a fancy way of saying that they both eat
food and use light for photosynthesis. For the most part, these corals
don't feed on phytoplankton (or, if they do, not primarily).
However, phytoplankton can feed these corals indirectly by feeding the
"critters" in our systems. These critters, when well fed, can
continually reproduce, providing a great source of "natural"
food for hermatypic corals. Feeding corals in this way is beneficial
also because it provides a more constant (vs. intermittent) food supply
(which is closer to how corals feed in the wild). [Note: In most cases,
it's best not to try to target feed your corals phytoplankton...
especially if the phytoplankton is cold, concentrated store-bought
product. The best way to feed phytoplankton is to either drip it in
continuously or pour it into a high current area of your tank.]
Another argument for phytoplankton feeding is that phytoplankton feeds
benthic and refugium/sump critters that help process waste. Keeping
healthy populations of these organisms can help keep your tank
"clean" and healthy all around.
Phytoplankton is also used in the culturing of zooplankton used to
feed, among other things, fish larvae. [Note: For some further reading
on this use of phytoplankton: The
Breeder's Net by Frank Marini]
Arguments against phytoplankton feeding:
If unconsumed, the phytoplankton will degrade and just become another
source of nitrogenous waste. This might be a concern in small systems
Your book is available in the Kindle Store! – 09/10/13
Oh yes; a new e-book on marine algae and their control in
aquariums; can be borrowed for free w/ Kindle, for Prime
members. Enjoy. B
Congratulations, your book "Marine Aquarium Algae Control"
is live in the Kindle Store and has been enrolled in KDP Select. It is
available* for readers to purchase
Phytoplankton Article 10/31/06 Hi, firstly thank
you for always being there, your pages are my bible! <The
Blessed WWM ;) > Just looking for info on phytoplankton, but there
is nothing there - wondering if you were aware of this, or
there is just no info, or if you had deleted the info for some reason.
page http://www.wetwebmedia.com/phytoplankton.htm Thanks again for
all your amazing information, Leigh Booth <Not deleted, just not
written yet. Should have some luck finding information
searching the FAQs. Hopefully soon the article will be added
to the holy pages.> <Chris>
New Print and
eBook on Amazon
Marine Aquarium Algae Control
by Robert (Bob) Fenner