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Re: Water for Daphnia (was Live Foods Digest V3 #148

Hello Tomoko,

First of all, the Daphnia did NOT die because you did not feed them!
They probably died form transfer shock, by being dumped into new water.
If your water is chloraminated, that probably also contributed to their

One of the safest ways to prepare water for a Daphnia culture is to use
old aquarium water that you removed during a water change. That water is
already "biologically safe". If it is cloudy and does not settle, then
filter it through a coffee filter.  

The problem, though, is probably not only the water, but also the manner
of introducing your Daphnia to the new water. It MUST be done very
slowly, because Daphnia are quite sensitive animals. That is the reason
why they are widely used for testing water quality!

The simplest way is to place your newly arrived Daphnia (in the water
they arrived in) in a a container and then SLOWLY drip in your new water
(siphon the new water through an air line with a knot in it, to regulate
the drip rate). If it takes you overnight -- so what? The slower you add
the new water, the less strain on the animals and the better the chances
of successfully introducing them to your water.

Once they start multiplying in your water, you should have fewer
problems with water changes. Divide the culture in two or three
containers and never treat, or change water, in all of them at the same
time. That way you will always have a backup culture if something should
go wrong with the culture you are handling.



> Date: Thu, 1 Mar 2001 21:04:39 -0600
> From: "Tomoko Schum" <tomokoschum at earthlink_net>
> Subject: Water for daphnia
> Can anyone recommend how to prepare water for
> daphnia?
> I just received a culture of daphnia pulex
> today. It took two days to arrive from the
> vendor. It was a small culture, about one
> pint, in green water.
> I could see only a small number of daphnia
> swimming around when I got the package. The
> vendor stated there should have been many
> visible in the bag. I put them in a bucketful
> of prepared water along with the green water
> they were shipped in. The bucket held
> approximately two gallons of water. The water
> was prepared last night in accordance with
> the method instructed by the vendor.
> (Tapwater filtered through PUR tabletop
> filter.) Since the water in the bucket looked
> slightly green, I didn't feed the daphnia
> before running out for some errands. Two
> hours later, I found all of the daphnia dead.
> I suppose the water was not suited for them.
> But I don't think my water is very high in
> chlorine, chloramine or heavy metal.
> Sometimes I forget to treat the water in
> which I hatch brineshrimp eggs, but the bbs
> hatch and live for a few days without a
> problem.
> Anyway, I am getting another batch from the
> vendor that should arrive on Monday.  So how
> should I prepare water for them?  I can go
> ahead and age the water that the first batch
> died in, or I can use rainwater that has been
> collecting in a bucket on my back deck
> through the winter.  Alternatively, I can go
> to the supermarket and get Evian to be sure
> of the quality.
> TIA,
> Tomoko