Cynops cyanurus fatalities

[froggy]

Hi all

A friend of mine (no, its not actually me) has a group of Cynops cyanurus, but is having problems with mystery fatalities. The animals are kept in cool water (about 12deg. C at the moment) with Elodea, rock hides and a floating cork bark island. All the newts seem helthy, actively feeding and behaving normally. However, a number have, over the last 6 months or so, mysteriously died. The deaths have been swift enough for the 'victims' to appear normal one day, and then the next dead. Today, while visiting, we noticed one animal curled up, cat-like, in the corner of the tank, underwater. When disturbed it was lethargic and unresponsive, even though the rest of the group were active an healthy looking. i think that this one will be the next to go. Animals of both sexes have died.

I am aware that cyanurus is a notoriously difficult (at least in Europe) species, but does anyone have any ideas of the cause of these mysterious deaths, or any tips to prevent them happening?

Thanks

Chris

 

[Jennewt]

My guess is that they're too cold. In my experience, C. cyanurus shouldn't be kept below about 16C for adults, or 18C for juveniles. My experience has been with a strain of "non-Chemnitz" cyanurus.

 

[froggy]

Aaaaaah. Thanks very much. I had always thought that cyanurus was a cold-preferring species....I will let Richard know.

Chris

 

[grunsven]

I have mine at low temperature (<10 celcius occasionally) and I know of someone who has them outside (at 3 degrees celsius water temperature currently).They become less active and do not feed as much anymore.

But these groups are both C.c. yunnanensis and offspring from a Dutch import (by Harry Dresens) and very easy to keep.
Do you know what they are fed?

 

[froggy]

They are fed a wide variety of live foods, including Daphnia, bloodworm and earthworms. All the other parameters seem fine and normal, and his other Cynops are thriving. Interestingly, they did do better during the summer when their tank was placed outside....perhaps it is temperature. I think that his are yunnanensis, but I may be wrong (they could be chengongensis (the spelling of that may be a little inaccurate, I am not Cynops man!) There are no other obvious causes of death. Dead animals look absolutely fine, other than being dead of course. He has one individual preserved in alcohol that he found very soon after death, but at least externaly there are no signs of disease. It is very strange indeed....as I said, all the animals look healthy and active until, suddenly, they keel over and die...

Is raising the temps to around 16degC a good idea to at least try?
A juvenile animal he had in a terrestrial setup also succumbed to mystery death.

Any suggestions would be most welcome...

Thanks

Chris

 

[Otterwoman]

Also, you didn't mention if you have a filter. I had a small Elite filter that shot water, that my animals would go right up to and and sometimes press against; I think it caused them internal injuries and they died. After I got rid of the filter the mysterious deaths (about one every week or two) stopped.

 

[froggy]

the water is not filtered but is heavily planted and is water-changed satisfactorily.

 

[Jennewt]

If all the mystery deaths occurred at temps below 16C, then I would suggest warming them up to that temp. My experience with adults is relatively limited. My adults don't have the opportunity to be below 16C (my "basement in winter" temp), so I don't know what their actual tolerance is.

With cyanurus larvae, mine consistently die if they are too cold (16C or less approx.). They don't die immediately, they just don't seem to eat enough to stay alive and eventually die off one by one. They do fine if I bring them to the warmer part of the house.

With juveniles, my most recent batch was doing beautifully well until the weather turned colder and their tank dropped to the "basement in winter" temp around 16C. They became very sluggish and stopped eating. Some of the ones I shipped to other people at this time died mysteriously - they looked fine one day, but then appeared to have drowned the next day. This was despite the fact that I had kept them in deep water (post-morph) for a couple of months prior.

So this is my basis for thinking that C. cyanurus (at least the strain that I keep) are not cold tolerant. I could be wrong, there may be other factors involved in the problems I had.

 

[Jake]

Jen-that happened to some of the cyanurus I received from you, and it happened to some from the same batch that I gave to a friend. They all looked great, but in the cold they just don't do well.

 

[grunsven]

Typicall seems that different strains from different regions have different temperature needs. These are apparently not tolerant to cold while the "Dutch" strain is

 

[John]

I take it the Dutch ones have their origins at Chemnitz? I was lucky enough to get a tour of their facility with Patrick Steinberger in 2000. They had several generations of cyanurus then.

 

[grunsven]

No these are not from the Chemnitz line. There has been a private import in 2004 and these animals were very prolific, and easy to raise.
I do not know of any offspring of CB in this line but all F1 offspring is relatively young so that might be the explanation.