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Re: deeding daphnia/moina
[Warning long post with gratuitous waffle :)]
Actually, imho, though yeast can be a great food for daphnia (I've used it
with a lot of success with D. pulex, though I just feed algae cultures
to my magna), I don't think it's a good idea. This btw applies to all dead
food imho.
It's so easy for an inexperienced daphnia enthusiast to foul
the culture by adding too much yeast to the container. Granted there is
less chance of this happening when using activated yeast, but the problem
with activated yeast is that a lot of pre-packaged products that you'd buy
in a store also contain additives like calcium sulphate (great if that was
all they added, save on the hard water), vitamin c (ascorbic acid, BIG no
no) and a few other things. Basically this kind of product (and I tested
this myself because I thought it would be a convenient source of yeast
from the local store) can drastically change your pH and water chemistry
[I tested it out with a regular dosage. My water has no permanent hardness
and some temporary, and is pH 7.2. My 15 gallon container's pH dropped to
6.5 in one dosage and would probably go further down if I had added some
more to it]. If you live in a hardwater area or use tufa rock or something,
it would act as a buffer, but activated yeast that has been treated in
this manner is definitely to be avoided imho.
Another factor with inanimate foods is that though they're convenient they
all have different chemical properties and can screw around with water
chemistry too. If you're used to using them you know what you can and
can't add, and how much. From my experience, D. pulex is a lot hardier in
this respect than D. magna.
The best food for all kinds of Daphnia is obviously free-living green
algae and/or euglena, even though they increase pH, this is relatively
easy to manage as Daphnia tend to be tolerant of high pH as long as there
aren't high levels of ammonia. The easiest way I've found for culturing
Algae are old sweet jars (about 1 imp gallon/4.5 litres each) filled with
old aquarium water and then add a small dog biscuit to the water (or tiny
piece off one of these biscuits, which are mainly meat), which is infused
with a few mls (as much as you like) of already prepared algae, and then
left on a window sill that receives a lot of light (but doesn't get very
cold) for a week, and hey presto, greener than green. I live in Ireland
and the highest temperature we get at this time of the year would be 20
degrees Celcius (about 70 F), and this works well. I've found that a 20
litre aquarium with a healthy magna population can clear 4.5 litres of
added green water within 3 days at 20 degrees C (we're talking see through
here, not crystal clear). So you really need at least 3 jars going at
once.
As an addendum though I asked about aeration and D. magna about a month or
so ago and no one replied, I decided to experiment and have found that
they thrive with a mild amount of aeration in the water, as opposed to the
pulex strain I have which doesn't seem to do very well in aerated water.
John
---
"Language has not the power to speak what love indites:
The soul lies buried in the ink that writes."
eirinn at valhalla_com (http://www.maths.tcd.ie/~jpc)