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Re: Live Foods Digest V1 #101

>I've been playing with daphnia cultures  (SNIP full text in LFD V1 #101)  They appear to be doing quite well.  

>

>This prompts the following question.  Prior to obtaining a daphnia

>culture, I did lots of reading about them.  Almost every source

>stated that using a bubble diffuser will kill them because air gets

>caught under their shell.  Their is no question that the air gets

>trapped.  (I did a quick harvest and tossed them in with my discus... 

>most of them buzzed around the top of the water and had trouble getting

>down.)  What I'm wondering is if the statement "supplemental air in

>a daphnia culture will kill the daphnia" is a myth?

>

Always intersting to hear about experiments and alternative methods of culture.

I doubt if air from an airstone got under the shell of the daphnia as they were swimming quite happily in the tank before harvesting, far more likely is the air drying the shell when you netted them out, giving the net a shake with the daphnia in it so that the cannot drop to the bottom is an old killie keepers trick for surface feeders. The only reason to add air to a culture is to provide a high oxygen content to either maintain a large culture, clear polluted water or hatch resting eggs. All daphnia cultures pulse even in nature were they will pulse in different areas of the pond so that while you may collect daily the cloud may be in a different area from time to time. Pulsing is caused by several factors such as lack of food source, water condition and temperature as well as predatory enemies. I have never found green water particularly good for feeding daphnia but the bacteria that feed on it are so I cultivate the bacteria direct in the daphnia bowl. Also again I have never had much success with indoor daphnia culture but good results with mina which can be cultured in 5 liter / 1 gallon jars, no air stone and if one pulses the others keeps going.

More detailed info on Daphnia and mina can be found in the back pages section of our web page.





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