Petshrimp.com Discussion Forum

I've seen this occur a couple times in the past 2 months.

One of my very oldest C. diminutus will die part-way through the molting process. It appears as if the claws and all of the legs do not make it out of the old shell and get ripped off of the body. The crayfish does make it out of the front half of its old exoskeletonbut not out of the part covering the abdomen.

I know that some crabs are said to have a "terminal molt" and can only molt so many times before death, but cannot find any reference to this with crayfish.

Again, these are my largest and oldest crays and I have never seen it with any of the smaller ones.

Sounds like crayfish have aging issues like everything/everyone else. Sooner or later something doesn't work right any longer...

I have had the same thing happened to some of my older crays from different species. I think it is something with age...is might be because their time to go has arrived.

-Pedro

I've observed this, and similar problems in both crayfish and Macrobrachium shrimp. I don't think that it has anything to do with inherent problems with molting. From my experience it has always been issues with water parameters....i.e. not properly "settled" or "established" tanks. This doesn't just happen in new tanks. If there are too many water, changes, too many fast growing plants and hence the nitrifying and other bacteria get disturbed and have to constantly re-establish themselves, then such "molting problems" occur more and more often. I'm not even talking about measurable water parameter problems here, but just slight ones, but bad enough to affect shrimp.

I've had macros lose both of their claws (seemingly *stuck* in the old molt) and a few legs during a molt. I can exclude the possibility of other macros attacking the helpless macro right after the molt, as in this particular case the macro was by itself in a tank. I've seen the same thing with crayfish. Once I correct the water parameter problems (which usually just involved leaving the tank alone and not disturbing it), these issues disappear.

Saw another one like this last night. It survived the molt but was left with only one leg and almost certainly won't survive. Several other molted exoskeletons were observed as well as two instances of mating.

I checked the basic water parameters (pH, nitrate) and nothing was unusual (ph=7.1, Nitrate less than 10ppm)

Again, this was one of the largest crayfish in the tank.

Do you know the life expectancy of these crays? Many dwarfs only live 1.5 years. If they were adults when you got them, this could just be their time.

I have one scientific paper reference suggesting that their life span is 1.5-2 years, and these deaths are occurring in my oldest wild-caught crayfish. So yes, you may be right that they may have reached their natural maximum age. If this was occurring with my younger captive raised crayfish, I would have more reason to be concerned.

I am not incredibly concerned since all my crays are apparently happy, eating, molting, and trying to reproduce as best they can.