Sorry for the long post...
Does anyone know the life-span/full-grown size of
Pistol Shrimp? I've had one for the last year that I really loved. He reached about 3"-3 1/2" in body length (add 3" of antennae and 5/8" of primary claws) He was a big fella.
Unfortunately, I think that he has gone...

Indications include no sightings in a week, no new sand trenches or banks in the last week, and his
watchman goby coming completely out of the hole...alone. The goby is also coming out of different holes within minutes, a practice not normally seen.
The last sign of him was what looked like a molt skin last weekend. I wasn't expecting to see him for a couple days, but a week seems to be a little long...
Along that line, I have also lost 3 cleaner shrimp in the last 2 months. The first was a year old, and looked like he died in a bad molt - I found his body. THe other 2 were only a couple months old. One just disappeared, the other was seen for a couple weeks, but without
any antennae

I thought he might die, without the antenae to feel/smell/catch food, he became very sluggish and hid most of the time.
I don't think it is a mantis, since I have not lost anything other than shrimp(?) and have not introduced any LR in more than 3 1/2 years. I have not noticed any snail or hermit crab (I only have 1) losses.
As far as water chemistry, nitrates are a little high, but not bad. Everything else is in-line.
Suggestions?
Thanks
Daryl