Lethargic Blue Crayfish

[zebbug]

Hello, I'm wondering if there are any crayfish care specialists around. My blue crayfish (most likely Procambrus Allenii) has not been her usual active self but has gotten lethargic lately. She does not eat anything, tried all her usual items like carrot, spirulina wafers, cucumber, etc but sits very still in a relatively open area under a branch. Nothing else is moving except the antennae and sometimes also the eating-hands. Occasionally she has a "hiccup" during which her whole body twitches up a bit. She does this hiccuping also if I go close to the aquarium or knock the glass gently.
Over the past 5 months I've done 25%-55% water changes every two to three weeks. I don't know how old she is, but she was the size of a small man's thumb five months ago and is now the size of a medium man's thumb. This condition started a bit more than a week after her last moulting, a couple of days after a water change, and has been on for about a week. She lives in a 30-liter tank. Haven't given iodine or any mineral supplement until today. Measured the water levels yesterday and they are as follows:

PH 7.6-8
GH 35.8-53.7ppmGH/KH
KH 4,5deg DKH
NO-3 (nitrate) 12,5-25mg/l
NO-2 (nitrite) less than 0.3mg/l
NH3/4+ (ammonia) less than 0.1ppm

Any help would be much appreciated.

[Crispy]

could your crayfish be getting ready to molt again? could be a rapid growth spurt? I wouldn't start treating meds until you know what is the problem (if any). up the water changes to once per week or even a bit more frequent and see if that helps.

[-Alex-]

Your crayfish should be much larger by now... Iv kept a few crays over the last years! Great Invert .

You have one major problem.... The tank as far too small.... Personally i think a blue cray should be in a 70L tank, minimum (20gal for the Americans here ) . A 30L is about 8gals.

Have you tested yout water... Having Ammonia, Nitrite and nitrate readings would clear up a few things.

[zebbug]

many thanks Crispy and -Alex- for swift replies!

could your crayfish be getting ready to molt again? could be a rapid growth spurt? I wouldn't start treating meds until you know what is the problem (if any). up the water changes to once per week or even a bit more frequent and see if that helps.

thanks, i too am trying to think positive but it is kind of hard... she's been immobile for a week now - only if I knock the aquarium she responds with a twitch. the colour is still electric blue, like fresh after moulting, none of that burgundy shade i've seen when she's about to moult. no spots of any colour or cracks whatsoever..

Your crayfish should be much larger by now... Iv kept a few crays over the last years! Great Invert .

You have one major problem.... The tank as far too small.... Personally i think a blue cray should be in a 70L tank, minimum (20gal for the Americans here ) . A 30L is about 8gals.

Have you tested yout water... Having Ammonia, Nitrite and nitrate readings would clear up a few things.

thanks for the insights. space is on a premium where i live but anyways i'm going to get her a larger thank when she grows a little bit more. was also thinking of getting her a friend of some kind. she's been eating like a horse, sometimes carrot/cucumber piece or a shrimp wafer twice a day, never left a piece uneaten. but now she doesn't fancy any of the usual treats....

edit; tank temp is about 20 degrees celsius (that's about 68F I belive)

readings are in my original post, here are they again:

PH 7.6-8
GH 35.8-53.7ppmGH/KH
KH 4,5deg DKH
NO-3 (nitrate) 12,5-25mg/l
NO-2 (nitrite) less than 0.3mg/l
NH3/4+ (ammonia) less than 0.1ppm

[-Alex-]

Ohh i really did drink too much last night..... reading were right in front of me .

Crayfish usually dont usually eat for a few days during molting... sadly a week seems a bit long.

Temp and water seem fine so best thing you can do is extra water changes a hope it recovers...

[DeadSulphurhead]

Hmm, does sound like it's molting. My royal blue crayfish never became lethargic for a week, only a couple days. Don't knock on the glass, if anything is wrong, why add additional stress?
My guess is it could possibly be stunting, in such a small tank, but it's body says it's time to molt anyway. Mine is approaching 5 inches after only nearly 4 months, he is in 90g and uses every inch of the bottom, running back and forth, climbing things. It may sound dumb, but you don't have enough room for him to exercise and build strength.

Are you having problems with nitrites? I see you have some in your readings, PWC until it's 0, more so than small traces of ammonia.
How come your test results are so widely varied? I can understand if you can't make out back to back colour shades on the tests, but your using up to 3 different possible readings for each parameter! ie; Ph 7.6-8 is 3 colours, Nitrate 5-25 is 3 separate colours on the test. I only point this out because it could mean getting the right help compared to incorrect info due to the readings being slightly off.

[zebbug]

Hmm, does sound like it's molting. My royal blue crayfish never became lethargic for a week, only a couple days. Don't knock on the glass, if anything is wrong, why add additional stress?
My guess is it could possibly be stunting, in such a small tank, but it's body says it's time to molt anyway. Mine is approaching 5 inches after only nearly 4 months, he is in 90g and uses every inch of the bottom, running back and forth, climbing things. It may sound dumb, but you don't have enough room for him to exercise and build strength.

Not dumb at all, makes sense, thanks. 5 inches - that's quite large indeed! Is it possible we're not talking about the same species? see here for image of this one, taken at the end of December, when she had been with us for two months.

Are you having problems with nitrites? I see you have some in your readings, PWC until it's 0, more so than small traces of ammonia. How come your test results are so widely varied? I can understand if you can't make out back to back colour shades on the tests, but your using up to 3 different possible readings for each parameter! ie; Ph 7.6-8 is 3 colours, Nitrate 5-25 is 3 separate colours on the test. I only point this out because it could mean getting the right help compared to incorrect info due to the readings being slightly off.

You're right - the large deviations in value are from not being able to match the colour and hence using the ranges of two colours. Nitrites should be fine - it looks like it's either zero or 0.3mg/l. It's the nitrates I'm more worried about - Please note, it's 12.5-25mg/l nitrates so two ranges! (not 5-25! :)) Here it says under 25mg/l should be fine but the less the better.. Any thoughts?

Regarding PH - I used a test kit that maxes at 7.6 but got a hang-on indicator type test which shows a weak 8. Hence 7.6-8. I'll try to do multiple runs with GH/KH/nitrates etc as soon as I have time.

thanks again!

[zebbug]

hello again, re-testing the water gave the following readings:

PH 8
GH 53.7ppmGH/KH
KH 4,5deg DKH
NO-3 (nitrate) 12,5 (2nd to lowest range on the test)
NO-2 (nitrite) less than 0.3mg/l (lowest range on the test)
NH3/4+ (ammonia) less than 0.1ppm (lowest range on the test)

after one partial water change she got quite active, digging and walking about like she usually did, and i thought it was for the better already. this might have exhausted her to the brink, not having eaten for so long time, and to my sadness i found her lifeless in her favourite nest the next morning.

in the following link pls find a video on memoriam of Rapu:

thanks everyone for your help. if i decide to get another crayfish companion i know where to look for expert advice.