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Re: Live Foods Digest V1 #71
>Subject: Daphnia and water circulation
>
>When I mentioned a few posts ago about water circulation, trying to avoid
>airpumps, the one reply said "why circulate the water?" I guess I was
>assuming one would want to do this to keep the nutrients available to the
>daphnia longer. So this has made me question my process of trying to keep
>indoor cultures. Is water circulation in the culture positive, neutral,
>or negative in effect? Has anyone tried both and decided one works
>better?
>
>Also, I keep hearing about Gram flour for food. Is it not true that
>decaying leaves will supply food directly/indirectly for the daphnia to
>consume? I believe decaying leaves supply bacteria with food, who are
>then consumed by infusoria, and finally by the daphnia. Is this correct.
>
>I keep losing my indoor cultures to over/underfeeding, and probably other
>problems. I'm trying to find a method that works. Indoor temp. ranges
>from 70-80F. Any suggestions would be helpful.
>pearlsco at u_washington.com
>>Subject: resting eggs?
>>
>>The temperatures outside are slowly following. Temps here range from 9C
>>to 15C. There are still daphnia in my outdoor container but very few
>>mosquito larvae now. In sifting through the water with a fine net, I
>>pulled up a lot of small green and black particles, about 0.2 - 0.3 mm
>>in size. Are these the resting eggs of daphnia? Can I do anything to
>>make em hatch indoors (aerating was suggested)?
>>
>I have a question similar to Steve Pushak's. Have tried gram flour as
>suggested for a week to rejuvenate any dormant Daphnia eggs in my 10 gal
>indoor tank. I have even raised the temp a degree or two but nothing has
>happened. I plan to siphon the mulm in my outdoor tub hoping to get some
>more dormant eggs and transfer to the indoor tank. Any more suggestions will
>be well appreciated. TIA.
>
OK as I am the one recommending GRAM flour as a food for Daphnia I had better reply to the above questions by telling you how I do my cultures.
Resting eggs are triggered by an abundance of food, good water conditions and a lack of adult daphnia.
I never aerate the water unless it has fouled or the daphnia / moina have disappeared. Aeration is then carried out until the water clears and is sweet smelling again. No food is added until new daphnia / moina are seen swimming in the water as enough infusorial food will be present from the high oxygen content breaking down the cause of the water fouling to hatch the resting eggs.
I always use mulm in my outdoor cultures and peat that has been used to hold killie eggs in my indoor cultures (this also cultivates tubifex, subject of an article on our web page soon) for the eggs to rest in. All my cultures have snails as well to eat any excess food.
I only culture moina indoors as daphnia never does as well for me indoors. Outdoors I culture daphnia which also provides gnat larvae and bloodworm courtesy of mother nature. Most cultures are in 5 liter bowls and are kept free of aquatic plants. These freeze solid during the winter but each spring at the first warm day the daphnia reappear.
I only feed thriving cultures and harvest often as doing so increases production. I use GRAM flour because it is cheap and works better that anything else I have tried (yeast, lettuce leaves, banana skins ect) but if anyone has any other suggestions let me know and I will try them. Never feed an emerging culture until a cloud of daphnia / moina is present (Cloud = about the size of a decent pea if netted, you will be surprised how many animals there are in such a small area).
The GRAM flour is mixed two tablespoons to half liter (1 pint) and only enough tipped in to lightly cloud the water. I have some moina cultures indoors in tall sweet jars with these I take a pinch of GRAM flour between my fingers and squeeze between my fingers into the water. Do not feed again until water is clear.
For more information see the articles on Daphnia and moina on the back pages section of our pages.
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