Sure, Adrian it is possible to culture Cladocerans.
What. How? Oh sorry. I'm sure this is a plot to get me to write something? OK
Many hobbyists culture daphnia, or at least they think they do. Hobbyists
worldwide have probably cultured nearly every type of Cladoceran, they just
call them all daphnia. My point is - what works for culturing daphnia will
work for most or all Cladocerans. It doesn't really matter which beast you
have.
My second point is that maintaining a long term, pure culture of Cladocerans
is VERY difficult and TIME CONSUMING. Cladocerans eat single celled algae
and bacteria (phytoplankton). To successfully grow Cladocerans first you
need to become good at growing phytoplankton (or algae cultures). And I have
several long papers on this!
In short: heavily fertilise some tap water (water treated with chlorine etc)
and leave it in full sun. Inorganic or organic fertilisers are fine (e.g.
horse manure, chook poo, superphosphate, liquid ammonium nitrate). Use
anything that will turn the water into a green or brown soup in two to four
days. This is your algae culture. If your algae culture is still clear after
four days, throw away the water and start again, but add twice as much
fertiliser. Don't add more fertiliser to the old water; trust me, it won't
work well. It may help to aerate the algae culture. After seven or eight
days the culture should be really green (or brown). You should not be able
to see your fingers if you put your hand in up to your wrist. Divide the
culture into four and use it to start four new cultures (add the old algae
culture and more fertilizer to new water). Because each culture will only
last about 10 days at the most, you should start a new culture every two to
three days. Don't try and start new cultures with old cultures that you
meant to divide up a few days ago. They're kaput. A hint - the bigger your
algae cultures are the easier the will be to maintain, and the longer they
will last. Once you can reliably keep your algae cultures going then you can
try growing cladocerans. Still interested?
Obtain some Cladocerans from somewhere or someone else. DON'T put them in
your algae culture containers. When you start a new algae culture use the
remaing three quarters to feed to your cladocerans. Put the cladocerans and
some algae culture in a cladoceran only container.You should start them off
at 2 or 3 per ml of algae culture. Count them in an eye dropper using a
magnifying glass. Keep the cladocerans well away from your algae cultures
though. Cladocerans destroy algae cultures and then starve to death.
Cladocerans don't need full sun, but it will help the algae to last longer.
When the water with the cladocerans clears it is time to feed them more
algae. By the time it clears you should have 10 or more cladocerans per ml.
Use some to start a new batch, and feed the rest to your fish.
In my opinion this is way beyond most hobbyists. It needs too much space and
too much time! An easier method is to culture a mixed plankton soup. This is
more or less what happens in aquaculture ponds.
Get some wild water from a creek or pond. If it is already green, all the
better. You need about one hundred litres or more. Put it in an aquarium in
full sun. Fertilise it heavily as above. It should turn green in a week or
two. Have a look at it with a magnifying glass. If you're lucky you will
have a plankton culture with heaps of little critters. You might be able to
use some of this to start another culture, but after one or two more batches
start again with wild water. When (not if) the plankton culture clears it is
time to start over. The culture may contain a whole range of algae,
bacteria, protozoans, rotifers, microcrustaceans (cladocerans, copepods,
ostracods) and terrestrial insect larvae such as chironomids (red worms) and
dragon fly larvae. You may also get water boatmen (or backswimmers) and
other nasty beetle larve. You should strain the undesirable beasties off and
feed them to your coal grunter (What do you mean you don't have a coal
grunter? How do you get rid of your excess fish?).
Once again the bigger the culture the longer it will last. An aquarium size
culture might last two weeks, a small swimming pool about 3 to 4 weeks, and
a quarter acre aquaculture pond 10 to 16 weeks. If the culture is still
green (or brown) it can be re-fertilized. Knowing when, and how much is as
much art as science. People who can keep a culture going have a truely green
thumb, and, no doubt, a wet bum.
Good luck, you'll need it.
Rob Wager
Freshwater Fish Biologist
Raintree Aquatics Pty Ltd
Aquatic Environment, Fish and Aquaculture Specialists
1002 Caboolture River Road, Rocksberg, Queensland, Australia, 4510
Phone 07 5496 7939, Facsimile 07 5497 0022, International +61 7 5496 7939
Email raintree at closer.brisnet.org.au