Crayfish molting duration

[Coyne]

My crayfish has been molting, or at least attempting to molt, for about 36 hours now. It has successfully molted several times in the past and it was able to do it inside of 12 hours. It would look normal in the morning, but when I'd get home from work the old shell would be laying about.
The only difference I can think of is that it has been a long time between its last molt and this one (almost a year, I think). Frankly, I thought it was done growing.

Its still alive... if I gently poke at it, it'll move around for a bit. I know that they can die if they have complications while molting though. Just wondering if anybody else has had it take this long, or if I should start worrying.

 

[aqua_holic]

Crayfish will never stop growing, though the time span between molts will increase with age.

In my experience they will drop limbs if they have to, in order to free themselves from the old shell.

How far along is the molt?

 

[Coyne]

At this point I'm guessing between 36 - 48 hours.


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[aqua_holic]

No i mean how much of the shell has been shed.

 

[Coyne]

Hard to say. It's kind of wedged in a corner between the glass and a rock. Right now it kind of looks like a weird monstrosity. The tail portion has come free, but I couldn't say for sure on the rest. If I were to hazard a guess, it seems like its stuck on the front "head and pinches" part.


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[aqua_holic]

Okay that's good - the face and claws are the last to come free. I don't really know what to tell you though... Nature has to take it's course.

 

[54seaweed]

36 hrs seems like a long time
I don't keep cray fish but do have a saltwater lobster he seems to molt every 6 months and it averages out to a 24hr period
I would think it would be about the same for a cray fish
heres a pict of a molt no loss of limbs it's all there it's a interesting transformation if you can catch it while it's happening

 

[Coyne]

Ok.. well, its not like I can help it along. I'll just keep an eye on it and give it a gentle prod every so often to make sure its still alive. I dont want to disturb it too much though.
Today is the day I normally do PWCs on my tanks, but Ive decided to skip its tank for now. Not sure if it would stress it out or not. Nitrates were between 5-10ppm, so there's not real rush for a water change anyways.

 

[Coyne]

it's a interesting transformation if you can catch it while it's happening

Yeah, this is the first time Ive ever seen it molt. Usually I either wake up in the morning or come home from work to find the old shell on the aquarium floor. Gave me quite a shock the first couple of times... I though it was dead!

Its kind of in a weird position right now though; which is making it pretty difficult to tell just exactly what is going on. I just gave it a little poke on its tail again and it wiggled its legs. Normally it would either move away or try to grab onto whatever I'm prodding it with. Also, after a molt I typically find him recovering in its cave. So I guess its the "atypical-ness" of things that's got me concerned.

 

[54seaweed]

keeping the lights off will help him feel more comfortable

maybe some soft music

 

[Fishfur]

Poking him while he moults, though I get why you did it, is stressing him out. They are soft and very vulnerable after a moult and during, and typically do it in hiding. That's why he hides afterward too. He's waiting for the shell to harden up. They can have problems, on occasion the shell can be too thick or hard and they can't wriggle out of it. Normally, once the shell splits, it should not take very long at all for the animal to finish moulting. Certainly not this long, so I'd say he's got a problem.

Have you checked the GH or KH of the water ? If it is very hard, that can be an issue with hard to moult shells, though not one you can fix right away, unfortunately.

If you think his position is interfering with him finishing his moult, gently slide him to a another spot, as close as possible, then cover him over with a leaf or bit of plant and wait to see if he makes it. He will be least stressed if he feels hidden. Lights out is a good idea too. Good luck.

 

[Coyne]

I was just barely prodding the very tip of its tail. I'm not super keen on messing with it even under normal circumstances.

The water is quite hard. It's been a while since I tested, but if memory serves the GH is 10-11 and the KH is pretty well off the scale (20+ drops to get the color change).

This is the sixth time it's molted and the first with issues. It's moved/shifted a bit and I can now see that the thorax (?) segment is completely separated. I couldn't say if that's a new development or if I'm only just now able to tell.


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[Fishfur]

That might be why it's having a problem. Very high KH is not desirable. Maybe you could start to dilute the water for them, using some RO or DI from the store, if you don't have a distiller or filter source at home. But it sounds as though he's making progress. I hope he's ok.

 

[Coyne]

That's a bummer. I did have plans on purchasing an RO/DI unit and 50 gal barrel in hopes of getting better results with my plants, so I suppose this is just further incentive.

 

[Coyne]

Well.. it didnt make it.

After getting a better look at things, it seems to me the only parts that didn't molt were the big claws up front. Head, body, legs and tail were all accounted for. In the past everything came off in one piece (more or less), but this last time it seems like they all came off separately.

Wish I had a better understanding of what went wrong. Maybe the KH issue, maybe old age, or something else entirely.

 

[aqua_holic]

Have you always let it eat it's shed shell? That's important. I also think it's important to feed them ghost shrimp.

 

[Coyne]

I would leave the discarded shell in the tank for 2-3 days and then remove what was left over (which was usually all more most of it). Its diet was mostly pre-made crustacean food that's supposed to meet the calcium requirements and I supplemented with veggies like spinach and zucchini.

 

[aqua_holic]

It's important for them to eat their shells - recycles nutrients. I have read that removing the shell leads to molting complications. I cannot speak to the accuracy of the claim, especially since sickness in inverts is just so difficult (impossible?) to determine. Mine would eventually eat all of their shells, over the course of a week or so.

Sounds like you have done mostly everything right, so it's a shame that this has happened. I think the only thing you might have been able to do to save it was break off the claws, not that that would have been guaranteed to work. Normally they drop their own limbs in that situation. Shame yours didn't.

 

[Coyne]

Who knows...
I had read that they'll only eat their shells if they need the extra calcium for the new shell and to remove any uneaten shell after a few days. Since this one rarely ate much of his/her shell, I just assumed it was because I was already supplying enough calcium in its regular diet.


I guess the average lifespan is 2-3 years. I had it for about 18 months, but I couldn't say how old it was when I got it. May have just been its time. I also think the tank may have been too small (10 gal), which might have played a factor.

It's a bummer for sure. It was kind of neat, but I don't think I'd get another.


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[Fishfur]

That's a shame. But sometimes life is less than kind.

There are some small species of crayfish that are probably more suited to a tank of that size, like the Mexican Dwarf.. often called a CPO. They're bright orange and grow only about 2.5 inches long. I'm afraid I have no idea of their life span, but they often reproduce successfully if you have both sexes. Can even be kept with shrimp, as they can't swim forwards, and shrimp can, so even if the crayfish would prey on shrimp, usually the shrimp can escape easily enough. The crays need hiding spots like shrimp do too.

If the moulted shell wasn't being consumed, it may well have been that the diet had enough calcium in it. I know my shrimp always eat theirs, though it may take awhile. I keep filter feeding shrimp also, who don't appear to be able to eat their shells,given the lack of claws to break them up with, but the little cherry shrimp usually eat those too, even though they're much bigger than their own moults.