Crayfish acting strange

[b125killer]

I'm not to sure if he's getting ready to molt but he has been acting strange the past couple of days. I have seen him laying on his side and back and has been lethargic. Also his color is a little off. I have seen him molt before and he didn't act like this the last time. it's been awhile since his last molt. I hope if he is going to molt and that he's not having a problem with it. 

[Mugwump]

How long do the shrimp live??

[BillT]

I have seen him laying on his side and back

This does not sound normal.

Molting it triggered by changes in hormones. It usually involves a series of behavioral and physical changes in the animal.
They will tend to hid to avoid predation in their more susceptible soft shell state. They will often change color as their skin cells delaminate from the inside of the old exoskeleton. I often had crayfish become less red and brown and more blue and white at this stage.  The old exoskeleton will become thinner as calcium and other nutrients are absorbed by the body prior to shedding it. After molting the new exoskeleton is soft, the crayfish tacks in water to expand its body size before the new exoskeleton hardens so that it has grown in size. Then colors return to normal.  Molting is often followed by eating the shed exoskeleton to recover additional nutrients. Other crayfish seem to be able to sense a crayfish has molted and will try to eat it. Hiding places (hidey holes to use an ecological term) are required of multiple crayfish are crowded together.

This is a complex series of changes driven by different hormones at different times. It can go wrong for various reasons leasing to various problems.

Interestingly, there is a gland in the base of the eyestalk that makes some of the hormones involved in this. Cutting off the eyestalks can in some cases trigger molting as I recall (can't say I've ever done that, sounds kind of gross). Thus some eye problems (damage in a fight?) may affect the hormones required to successfully coordinate the molting process.