My Blue (Crayfish) is dead! He did indeed get ready to molt as some of you had suggested, he managed to get rid of his exoskeleton completely, he looked perfect under that, yet he did not make it. I gave him two days, because I wasn't sure if he was dead or not, but when I peeked in to his hut to check on him, on of his eyes was already missing and he had changed the overall color- when I fished him out the smell was overpowering! I miss my little feisty "Put'em up" guy! I'm sure it was me who caused this! I did not kknow aobut the behavior when they get ready to molt and disturbed him, when he was still in his armor. Even though he made ti stil out fo that he couldn't go on! I feel like crap, the only comfort I take is that if I do decide to get another one down the road, I will know all of the signs and wait for him to snap out of his catatonic state instead of trying to find out if he's still alive.
I'm sure it wont help you feel better, but i think you had little to do with the poor guys death. "sudden" death is something you get used to with, many, inverts. especially after a moult. having reviewed you other posts, i don't see much you could do better. few hints for the future:
try to keep your cray, if its a REDCLAW, at about 72-74f. they will be quite happy, but the lower temp will help keep in check Bacterial infection, something Crays suffer from.
try to feed less meat, often a source of bacteria. and they are not carnivores but omnivores, so without access to a large amount of veg matter they don't do as well.
Hides, you, often, need 4 of 5 hides for one cray. one they live in, one, possibly more, they will move into after the next moult and a couple it can drag food into as it eats.
PH cray do not do well if the PH is less than 6.6, some say higher. this gives the cray problems as there is not enough calcium to harden the shell. be warned though. cray do not get their calcium from food. they absorb it via their shell, between moults. so you need to be vigilante at all times.
Iodine. a few drops of Aquarium Iodine, around moult time, will help no end.