Is it normal...

[thewesterngate]

Is it normal to have a die-off of young daphnia after shipping? I received a starter culture yesterday after only two days in the mail, split them into a fervently cleaned plastic litter bucket and a 20 gallon plastic bin, then fed them yeast water. Those adults with the axolotl eggs, and in the litter bucket seem to all be accounted for..but the majority of the baby daphnia were in the 20 gallon bin, and well, they aren't there anymore. Aside from the dead daphnia dust at the bottom. :crazy:

I worry. A lot. This is just the tip of the iceburg. I dechlorinate all of my water with Prime, being that I'm a pretty big aquarist, but perhaps I should've aged it more..I also had some aeration, which I cut back on..but maybe it was a little too much for them. And yes, I've read just about every piece of literature I could find about daphnia and I'm still worried! I want to make sure these axies have the best chance of survival.

Thanks for reading my mini-rant, and any thoughts are appreciated!

 

[thewesterngate]

Update: HRRRGH. Okay, so..it was my fault. I'm not sure what went wrong, but those in the bin are all dead. I must have left some of the 'aquarium safe' cleaner in it..but I thought I'd rinsed it all out. Gah, this is terrible. I still have a handful, but not nearly enough for the babies once they hatch. I guess I'm going to have to order more since my LFS doesn't carry them.

 

[shredder83]

When I received my daphnia culture I had the same thing happen. Most of them died not long after I received them.After a few weeks they are starting to repopulate. I have a 16 gallon tub for my culture. I use an open airline tube with a very slow flow, slow enough that you can count the bubbles.
Put a bright light over your culture and wait a few minutes you will see them coming towards the light. That should help you determine how many you have left.

 

[SludgeMunkey]

Aye, a good many will die in shipping. Quite a few more will expire in the following days.

the secret is to skip the tap water all together and use dirty tank water for them. New cultures are very sensitive to chemistry and temperature changes.

Definitely save the failed culture though! Dump it into a 5 gallon bucket of dirty tank water, add a few drops of Amquel+ and forget about it for a few weeks in a sunny place. If you are lucky, the culture will restart itself for you if you keep it topped off with dirty tank water.


Generally, when I order daphnia online, I buy three times what I need to start a culture and then split some of the shipment into a small "reserve" culture until things get going full bore.

 

[thewesterngate]

Thanks you two, maybe it was just due to the shipping. I still have 10 or 15, so I'm sure I'll get a culture started..but with my luck, the babies started hatching today! I have six so far. Gaaah. I'll start them on BBS tomorrow and my new order of way more daphnia than I need will be in Tuesday. :grin:

 

[DR]

With most of the juveniles dying, it will have been acute toxicity.

Basically osmotic shock and electrolyte balance from de-chlorinated water.

 

[thewesterngate]

With most of the juveniles dying, it will have been acute toxicity.

Basically osmotic shock and electrolyte balance from de-chlorinated water.

Wouldn't an electrolyte problem only be the case if they were moving from salt to freshwater? And since the daphnia are freshwater species..not sure.

New question; I have a plethora of copepods and planaria in the hatchling tank from the water plants I introduced before they were hatched. Being that my most recent batch of BBS died (I should've fridged them)..what are the changed of the axies going after copepods as a food source for the time being? They're the same size as BBS, and I'm just curious. I'm going hunting for daphnia today since the biological site I ordered daphnia from hasn't gotten back to me..

 

[DR]

Wouldn't an electrolyte problem only be the case if they were moving from salt to freshwater? And since the daphnia are freshwater species..not sure.
.

No not the case, Salt is just one soluble compound in water, water chemistry is a complex subject, there are well over 40 water parameters (that are measurable)in freshwater alone so many factors.

Tapwater (generally speaking) with have little electrolyte activity or conductivity. This alone, can be very destructive on the gill membranes. This is why you should use old water.

It is also a myth that daphnia need 'hard' water, they'll grow in almost any water.

They are however, more sensitive to toxins in softer water, therefore more likely to show fatalities than if they were in hard water.

It's what we call increased sensitivity in the toxicity world.

 

[John]

I hear a lot of absolutes being thrown out here. In all likelihood what killed your Daphnia was the change in water chemistry - not that the new water was bad, rather it was significantly different to what they were accustomed and the shock was too much for most of them. However, every answer you're getting here is just speculation on everyone's part.

Regarding the "myth" of hard water, as DR calls it, it depends on what you consider hard water. Make no mistake, Daphnia require calcium to build their shells, so they require some dissolved calcium salt content. While hard water has this in abundance, most water sources with a pH over 7.0 contain some calcium salts that the Daphnia can use, and therefore these waters have "hardness".

 

[thewesterngate]

I hear a lot of absolutes being thrown out here. In all likelihood what killed your Daphnia was the change in water chemistry - not that the new water was bad, rather it was significantly different to what they were accustomed and the shock was too much for most of them. However, every answer you're getting here is just speculation on everyone's part.

Regarding the "myth" of hard water, as DR calls it, it depends on what you consider hard water. Make no mistake, Daphnia require calcium to build their shells, so they require some dissolved calcium salt content. While hard water has this in abundance, most water sources with a pH over 7.0 contain some calcium salts that the Daphnia can use, and therefore these waters have "hardness".

No matter what it was, I'll definitely go easier on them this time. I figured they were hardy enough for the transition, but I've managed to keep wild-caught daphnia and other water critters alive for the last few days..so I'll be able to acclimate the new batch of daphnia. Luckily I only lost one axie (deformed) so they're eating what I have been feeding them. Thanks for the input.

 

[DR]

I agree with you John but what I should have made clear was a little bit of KH and not so much GH (1 degree) would constitute relatively soft water,

It's difficult to diagnose from a far, so for that reason I can only speculate.

 

[eyrops]

I a little bit of KH and not so much GH

The acronyms have sent me to my Limnology text, but I'm still confused. Is GH German Hardness with one degree = 10 mg CaO / l-1 ? What is KH?

-Steve Morse

 

[Jennewt]

GH = general hardness
KH = calcium hardness