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Koura Moulting... slowly?


Mikey

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Hey all,

My Koura has been moulting for several days.

I can see the split between the upper and lower carapace, and it is slowly getting bigger... is this why they hide? Or is he having trouble wriggling out this time.

I have moved him twice, and he has flicked away powerfully, but apart from that he is literally just sitting there. I wasn't too worried when I first noticed because he has moulted 6 times since I had him and normally goes fine, but this has been 4 days since it started. The split has grown from about 2mm up to about 9-10mm now...

So, can a Koura get stuck moulting? and is there anything I can do to help, or do I just keep an eye on him and see how it goes?

I was going to take some photos.... but wife has camera in Germany with her :facepalm: I've got a couple on my phone camera, but not great quality.

PS: $10 says I get home from work and I see he has moulted and running around happy as a larry.

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Checked on Koura this morning.

Seems very dead &c:ry

The upper carapace looks like it has peeled off overnight. Not really sure what has happened, water parameters were all fine. Not sure if he had a failed moulting or something more sinister occured.

I am disheartened right at the moment... everything was going so well, but things change pretty fast I guess.

I'll post a pic or two from my phone camera this evening so people might be able to help out? Otherwise I'm going to do a bit of research on the net to see if I can find some extra info as well.

Talk again shortly.

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OK, so I have fished him out... taken some photos:

Please forgive the quality, they are off my phone camera because my normal one is in Germany with wife :rotf:

So here is a couple from a few days ago... you can the split in his carapce... that is the white line you can see in the middle of the pics. This is when I went to Stellas book, had a bit of a read, assumed he was just moulting and left him to it...

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And here he is fished out... the shell was a bit soft and squishy... but that might be because he had to sit in the tank for the day...

This one can see the gap that grew over time.

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Closer up view, bit of gunk in it, and there is the funny white stuff on the left hand side of the cray (top in this photo)

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And this one is the carapace lifting off very easily, and staying up, underneath there is not really much there.

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Now that I have fished him out, I'm beginning to think this wasn't a failed moult, but something more that I didn't recognise the signs of. :dunno:

He was on a regular diet of peas, worms, shrimp, broccolli, courgette, trout pellets, cockroaches and a few other bits and pieces, water temp never went over 20 degrees, and had a weekly water change. So I'd like to think I did every thing I could in terms of living conditions etc...

So theres what I have so far... as said earlier I will try browse through some other sites to see what this might have been. Any theories or help would be appreciated from the experienced on here :)

Cheers.

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Not enough Ca? just a thought.

Yeah, that's why I posted his diet... is there anything missing? I thought it was pretty balanced and the fact he moulted so frequently I assumed he was getting enough.

saw a crayfish in a marine tank with a similar wound once, it had a rock fall on it and had ripped it when it jerked itself out

I'm going to put some time into the tank this weekend and give it a revamp... I had a closer look and it seems he has excavated down to the glass under some rocks down the back of the tank... maybe one of them slipped onto him. I haven't checked close enough to see if one has slipped significantly or not with the alterations he made :)

In future if I see something like this on a cray, I'll be doing extra water changes and getting some salting going. I think what has happened is that he has gotten injured, I mistook it for a slow moult and his injury has gotten infected and taken him out. I'm feeling guilty that I didn't act sooner... but I have learnt from the experience, so am better prepared for the next time (if it does happen again).

Cheers.

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Weird, sorry for your loss :(

Moulting can be a difficult time for koura. Interesting observation by LivingArt that it can be water quality at the time of moulting! I am pretty sure it is an issue in the wild too, but perhaps water quality could exacerbate it in captivity.

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I was wondering why my koura was in a grumpy mood the other day, chasing any and every thing around the tank if they go too close, the day after there is an empty carapace in the tank

hehe I think they suddenly feel invincible after they have moulted and hardened - they are aggressive little sods afterwards!

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  • 5 months later...

Hi,

Just the same thing happened in my tank now, water quality just fine, everything else good, fish are happy, enough food, and koura start dying, sad thing.

I will check the Ca2+ concentration but I doubt it is the problem since I put in some crushed shells months ago, pH is good although has a high buffer capacity. I left the previous left overs from moulting in the tank to keep the Calcium in the system. I have quite a few shrimps in the tank as well but did not think they would take too much calcium away. Do not think it is the problem but will start to check everything out step by step before I put new crayfish in later this year.

Let's hope it is something easy to fix.

Mikey did you find out more since the last posting?

Cu

Daniel

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Hello livingart,

Agreed that temp. and DO play a role in water quality but normally they should be fairly stable in an established system like mine for example,

14 degree, and above 6.5 mg/l O2. Which is good enough to grow demanding species like trout, that does not cover it quite well enough for me.

There must be something else going on, with still plenty of options like the nutrition in the food is not good enough, stress with too many animals, not enough hiding spots, injuries, not enough Ca2+ available from the water, infections (bacterial, virus, fungus), etc. Would like to get in contact with somebody who has a koura farm but I do not know anybody here up North, they should have come across problems like that and might have an answer.

Just keep going and try to find out more about it step by step.

Cheers

Daniel

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Hi,

Just to keep going on the topic, I checked Ca2+ and 5mg/l as low level is suggested as alright still but optimum would be 30-30 mg/l. Mine are rather 60-80 mg so more than that not sure if that level is a problem but would not think so. Try to find somebody who grow them up north here for any reasons to have a chat about it. Does somebody of you guys know someone north of Auckland doing that?

Cheers

Daniel

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Hi Beezel,

I'm still not sure what took out my koura, could have been water temp spike that I wasn't around to see, everything else seemed to be ok, and his tank had a water change only a few days before he had his issue.

So I'm really at a loss as to what happened, it could just be one of those random things that happen from time to time in the wild that I happened to witness and trying to find a reason. :dunno:

I haven't got another Koura as yet, all I have done with the living creature part of the tank is chuck 20 mountain minnows in there so there is something moving around and keeping the good bacteria alive. I've been meaning to go out and at least get some shrimp, but life (aka young kids) keeps getting in the way of my night time excursions :)

Cheers.

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