Rearing N. crocatus (and derjugini), advice needed.

I've been lucky enough to get my hands of a nice amount of N. crocatus larvae (11) and N. derjugini eggs (6).

The derjugini eggs have hatched and are all beautiful larvae.
A couple of other people have gotten crocatus at the same time as me and I get reports from them that larvae are dying without explanation.

Luckily my animals are still doing fine, but I feel warned by the reports.
I'll describe the way I keep them and what my plans are. Tips and experiences are VERY welcome.

I currently keep my derjugini larvae in a small plastic container (20*10*5cm approx). My crocatus have a little bigger enclosure.
With axolotl and triturus larvae I had good success with this setup. I'm affraid that I can't monitor the little ones in a bigger enclosure.
They are at room temperature, around 19-23C. I do partial water changes every day to prevent a huge buildup of ammonia etc.

There are currently no plants in there or any hiding places. I've seen some nice ideas in 'the' N. strauchii larvae topic, so I'll add some small rocks today fro them to hide near. I'll also add an air pump to it to gently aerate the water.

It's difficult to see if the smaller animals are feeding well, because I can't see filled bellies very well, they just remain slender. I feed them daphnia filtered for their size. The crocatus will eat all sizes, but the derjugini only take the smallest.
I tried hatching some BBS, but I think those eggs gone bad, so I will buy new ones very soon. Luckily I have a big supply of daphnia so they won't starve.





These pics were shot at June 11, so the animals have grown a bit since. These are all crocatus. I forgot to upload my derjugini pics, they will follow soon.
The pictures aren't the best in the world, they were hastily shot.

I can't speak for these two exact species but I have raised both strauchii and kaiseri which probably require very similar larval care. In my experience the more sensitive Neurergus larvae do best in well established, well aerated tanks. I had massive kaiseri die offs when I tried keeping them in almost clinical conditions with frequent water changes. The problems occurred very early on, long before rear legs appeared. Once they get past a certain development stage they seem to become more robust but in my case that might just be because I ditched the clinical approach. I included dense rafts of floating hornwort in the larval tanks which not only gives the larvae somewhere to hide but will help suck up any excess nutrients. Your's already have back legs so I'd say they are doing well with whatever cleaning/feeding regime you have in place. As they say, if it ain't broke, don't fix it.

Not sure if that helps but good luck raising them!

I had the same problem that Mark states here. Massive deaths in early life when trying to keep them under clinical conditions with many frequent water changes and so, specie was Paramesotriton guangxiensis.
Most larvae from stream species have this problem. What I would advise you would be the biggest tank you could manage with enough room for your larvae, totally cycled, with a few logs, many living plants and with a small filter, maybe external if possible. This should make the trick since I stopped losing those many larvae once I started doing this.
Cheers,

A little update:

The animals are doing great. I can see quite a big difference in larva sizes in crocatus. I'm going to separate them so that bigger ones don't eat all the food for the smaller ones. The derjugini are showing back leg development. They're all eating great and no problems whatsoever.
I'll take some pictures soon.

If I promise pictures, I should upload them...
These are from around 2 weeks ago. The N. derjugini developed back legs by now and eat like crazy.
I lost 1 N. crocatus larva, but it had problems keeping up with the rest. The derjugini were already bigger than that one, so it must've been a weak individual. It sucks, but I was kind of expecting it.
All animals moved to a bigger enclosure with an air bubbler. They started eating small red mosquito larvae, so that's a good step forward.

Neurergus derjugini:










Neurergus crocatus:

Now that the larvae are morphing, they start dropping like flies. I lost 7 Crocatus and 2 derjugini within 1 week. All after morphing and on land. Animals that were lively and active yesterday are dead today. Some of them were pretty skinny due to the morphing process, others were nice and fat.

Does anyone have any idea what is going on?

What's your morphing set-up like? And how do you house them once they're out of the water?

Once out of the water I remove the water part and replace it with a water dish. I keep them on coconut fiber.

The morphing setup is the same, but then the water part is still there. I put stuff like rocks in there so they can exit the water easily.

Have you tried keeping the crocatus 100% aquatic after morphing? I think they can skip the terrestrial phases (like strauchii). Perhaps too with the derjugini. If they are doing well in the water it might be safer to keep them there. With terrestrial Neurergus kaiseri morphs I've kept them quite dry and given them plenty of dark hides to keep stress to a minimum. I think keeping them away from wet substrate aids the skin change from shiny/smooth to dry/granular. Perhaps during this transition they are vulnerable. I always feel more confident about a morphs chances once they have a dry skin, although I don't know where that feeling is founded. Do the ones that die develop a dry skin?

damien said:

Now that the larvae are morphing, they start dropping like flies. I lost 7 Crocatus and 2 derjugini within 1 week. All after morphing and on land. Animals that were lively and active yesterday are dead today. Some of them were pretty skinny due to the morphing process, others were nice and fat.

Does anyone have any idea what is going on?

Click to expand...

I don't understand Danny, You said on salamanders.nl '' 4 of your morphed animals where drowned. While they had enough places to go on land .. '' So not all died on land right. Maby allso good to manssion (Just a tought) .

2 of them (crocatus) were found dead in the water, that is correct. So many died the past days that I'm losing track

Yesterday I found one of my derjugini larva floating and with trouble with keeping balance. I put it in a smaller enclosure with water that barely covers it. I put a drop of Esha 2000 in there in case it's bacterial.
The rest of the larvae are doing fine. Eating great and active.

I have to say, this is the worst experience I've had in the hobby so far.
A few deaths due to inexperience, I can live with, but this is just cruel

Choice over environment usually helps morphs to settle. You could try a more complex setup with lots of stacks of cork bark, stones and some leaflitter with lots of invertebrates seeded into it (white-worms, springtails etc). The morphs may be better able to regulate temperature, humidity etc and so may do better. Sometimes this works as a last resort if you can't work out what is going wrong...

Good luck

C

I got a PM asking how it all ended, but I couln't reply (PM disabled?), so I'll just post it here for those interested.

Unfortunately I lost all but 1 crocatus and 3 derjugini. The remaining animals are doing great and eating without problems.
In Gersfeld in november I was able to get 5 crocatus from the same location, so I have 6 crocatus.

I also got my hands on 3 derjugini, but due to a stupid accident relating a heating mat from my firebrat breeding tank (forgot to put it back under the breeding tank, and it was leaning to 2 enclosures for like 2 days) I lost those 3 derjugini along with 5 of my 6 N. s. barani juvies that were well grown. Needless to say this hurt like hell. For this I'm fully to blame. I did (re)learn a very valuable lesson that I since repeat to myself everytime I tend to my animals: Keep your mind at what you're doing!

Posting this particular failure is part of my personal punishment. The image of those poor animals will not easily be removed from my memory. It's hard to like yourself on those days.