crawfish in aquarium

Question
Hi Karen, I hope you can answer our question, we have 2 crawfish in our aquarium, the one is about 8 to 10 mo old and quiet large she has had eggs twice,but nothing has hatched, however this time the eggs are a light (white) color, but they were black the first time, anyway my real question is for about a week now the crawfish has been laying on its back most of the time, we turn it over but in a short time its back on its back. She still has some eggs but not as many as she had about 2 weeks ago. Do you know why this might be??  It is out in the open aquarium while the other one is hiding in a house.  I have thought for a week that it was dying but not so. Do you know what is causing this and what we can do for it.
Thanks in advance for any help you can give us on this little matter.


Answer
Dear Liz,
I'm currently doing research on this whole thing and I'll try to get back to you with more info as soon as possible.

That is very strange behavior your Crayfish is exhibiting. I'm not really sure yet why she would be laying on her back. I know that with aquarium fish, if they start behaving odd it's always best to do a large (40-50%) water change just to be sure the water quality isn't the problem. It would also be great if you could test your water to know the ammonia, nitrites, and nitrates.

My next thought would be maybe she is trying to molt her outer 'shell' This is a possibility but I'll keep researching and trying to find out the answers. I won't keep you waiting too long.

Best wishes,
Karen~
----------------------- {Followup below}
Liz,
After lots of research, I've found out that crayfish laying on their back or side is a very common occurance. Sometimes people aren't sure why they do that. Many crayfishkeepers believe it is related to molting or eggs.

One thing you have to watch out for is if she does have eggs, that they don't become fungused out while she is still holding them. This could cause her some bad problems. If this occurs, you will have to try gently removing the fungused eggs yourself. You might want to carefully look her over and see if anything is abnormal looking about her underdside or anywhere else. Crayfish can get sick. But I'm not sure if that is what is -really- wrong with yours.

And as I mentioned before, making sure the water quality is very good in the tank and the water is well oxygenated is always a good precaution. If you can try to test your water.

What kind of filtration is on this tank?

The egg color changes can depend on a variety of things. Usually the eggs will change color because of developing young crayfish within them. Usually they may start out black and then later get less and less black in them. Whitish eggs may just be infertile.

If I come up with anymore information, I'll be sure to let you know. I hope nothing is seriously wrong.

Best wishes,
Karen~
----------------Below is another followup--------
Because I've never experienced something like this myself when I had Crayfish. I've asked crayfish experts/long-time keepers and here is what they said about the crayfish's behavior of lying on their back:
"We Have seen them do this;

   * with a bacterial infection
   * when they are laying eggs
   * when they are inter moult
   * when too much chlorine in the water
   * when nitrite is high
   * when the oxygen is low
   * when the pH is basic

Could be any number of things. Questions that is best to ask is, have you tested the water parameters for nitrite, ammonia and what is the pH level? Have you done any water changes recently? When we have a little more information about the tank size and perhaps filtration if any, aeration etc, then we can help."

That is their take on odd crayfish behavior. If you like, and if you wouldn't mind giving more info about the aquarium then maybe we can narrow down the list of possible causes and maybe even find the real trigger.

Best wishes as always,
Karen~