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Re: Live Foods Digest V1 #101

Hi all!

	I would agree with David Robinson that air diffusion is useful both in
raising daphnia indoors and greenwater indoors. The oxygen exchange is
important for the daphnia and the water movement (and oxygen exchange?)
in a greenwater culture will keep the greenwater from settling to the
tank bottom (dying?)

	This has been graphically illustrated a couple of times to me. The
first was when we visited a killifish person in Chicago's southwest
suburbs. While wandering around his fishroom I noticed a 32 gallon
rubbermaid trash can with the water literally "rolling" from the action
of an airstone with a considerable (near maximum?) quantity of air being
pumped through it. Grabbing a flashlight to illuminate this mystery
barrel in the dark, I was astonished to discover about the heaviest
concentration of daphnia I had ever seen in a such a container. The host
explained that they could be in the dark because he exclusively fed them
dissolved baker's yeast. Baker's yeast can easily foul a culture if over
fed, but he evidentally had a good feel for the art of feeding the
culture and the movement of the water may have compensated for slight
overdoses of yeast.

	More recently I moved a barrel of daphnia indoors as fall came on. The
natural movement of air outside must be considerably more than that in a
fishroom, because that culture couldn't have been producing 10% as much
indoors as outside - and temperature and feeding changes can not account
for all of that difference,

	When an airline was run into that barrel production of daphnia
increased several times. After all we heavily aerate our brine shrimp
cultures. Forgotten baby brine shrimp cultures will usually reward one
with a few adults if the air is just left on. For purposes of culturing
we can think of daphnia as fresh water brine shrimp.

	If there is a junior or senior high school person out there looking for
a science project maybe they can investigate the effects of various air
quantities (and foods, frequency of feeding, size of rearing containers,
surface area and so on) in daphnia production. (I'll send any kid a
culture if they will share their results here.)

	By the way, a green water culture in anything from a gallon jar to a 55
gallon tank will do better with a couple of fish (odd numbers, extra
males, youngsters in need of growing space). The fish help keep the
water moving and their waste material fuels the greenwater growth. Also
keep as big a light as is reasonable on a timer and have NO green plants
in there since they would compete for nutrients with the greenwater
organisms. Half of a thriving greenwater culture can be fed off to
daphnia (or rainbow fry or whatever) daily. The Euglena, Paramecium, et
al are remarkably adept at reproducing in a hurry. The water added to
the daphnia (and the calcium therein) will just keep things perking.

	Recently explaining this at my local aquarium club caused a member to
grim and realize why he had been unsuccessful in getting greenwater OUT
of one of his aquariums. His water changes were just as beneficial for
the greenwater as everything else in his tank!

				All the best!

				Scott Davis