Newbie Daphnia panic!

[fiddlersmrs]

Hi. I'm about to receive some Axolotl Spawn and have set up a couple of Daphnia cultures in preparation. A lot of the Daphnia arrived with black dots inside them. I'm guessing that these are the eggs which they produce when overcrowded etc?

There was an article attatched to the internet shop I ordered the Spawn from which states that when they fed Daphnia from the local pond (with black dots inside) 95% of the Axolotl babes died. He put it down to the black dots being indigestible.

I'm a bit panicked about harming the Axolotls by feeding these Daphnia to them, but don't have another supplier available at the moment. Could the eggs have been the problem, or was it more likely that they harboured some sort of disease from the pond as they were wild caught? I've not seen any other warnings anywhere, but really want to make sure.

cheers

 

[DR]

Newborn Axolotls should only be preferentially feeding on the smaller juvenile daphnia.

It is unlikely they were feeding on the adults (which only produce winter eggs).

Even if this was the case, chitin is partially digestible, and if not completely digested, they should be passed out in the faeces.

95% is a huge mortality rate, axolotls and newts naturally feed on daphnia, if winter eggs were so deadly, then there would be these high mortalities in the wild.......this is not the case.

There are problems when fish fry are fed too many husks from artemia eggs/cysts. But then, artemia are not a natural food for freshwater tropical fish.

More than likely, the wild source has harboured pathogens (bacteria or protozoa) accounting for the high mortality.

 

[stanleyc]

I have been feeding my C. Orientalis larvae with some daphnia with the eggs, and they have all been fine, no casualties yet.

 

[fiddlersmrs]

Thanks

 

[Azhael]

None of my dobrogicus larvae have any trouble consuming Daphnia that carries ephippia.
Neither do any of my newts, except, curiously enough, my I.a.apuanus. They enjoy catching Daphnia, but i could see how they would spit out those that were carrying ephippia.
Perhaps they taste bad ? and just like with E.foetida, some animals tolerate it and others don´t?

I, however, doubt very much that the mortality of your axolotls was caused by the ephippia...
Daphnia produce these resistance eggs when conditions are not apropriate or densities are too high, so maybe they were producing ephippia because something was wrong...and that something wrong affected the larvae.