Emerald Crab Die Off? Mass Molting?

[AGWL]

Hi all,

No pictures because I didn't think to take any.

I've 4 emerald crabs.

My smallest had a trauma several months ago and was down to 2 legs plus his claws. He's been in separated from the main tank until he molts and regenerates some legs. He's very tiny but feisty.

My next small one, a ruby, is fine and has been out and active more than usual.

My middle one was belly up the other morning. I couldn't tell if it was a molt or death (it's so much easier to tell with shrimp). I assumed he died as I'd found him the day before upside down trying to right himself.

I found my largest one, who was magnificent, this morning. Unable to tell if it was a molt or death.

In the year I've had them, I've never been able to confirm a molt, although I'm pretty sure the big one did at least once.

No scavengers were bothering the "corpses".

I'm running chemistries now. 60g mixed reef. Everyone else is doing fine.

Is it possible they both molted around the same time?

 

[ISpeakForTheSeas]

In the year I've had them, I've never been able to confirm a molt, although I'm pretty sure the big one did at least once.

No scavengers were bothering the "corpses".

I'm running chemistries now. 60g mixed reef. Everyone else is doing fine.

Is it possible they both molted around the same time?

It's possible, yes. For confirming if it's a molt or not, one sure fire way to tell is to cut it open - if it's really a dead crab, it'll have meat inside (and it's already dead, so no harm done); if it's just a molt, it'll be empty.

 

[The_Paradox]

Full moon so it’s possible.

 

[kevgib67]

Hi all,

No pictures because I didn't think to take any.

I've 4 emerald crabs.

My smallest had a trauma several months ago and was down to 2 legs plus his claws. He's been in separated from the main tank until he molts and regenerates some legs. He's very tiny but feisty.

My next small one, a ruby, is fine and has been out and active more than usual.

My middle one was belly up the other morning. I couldn't tell if it was a molt or death (it's so much easier to tell with shrimp). I assumed he died as I'd found him the day before upside down trying to right himself.

I found my largest one, who was magnificent, this morning. Unable to tell if it was a molt or death.

In the year I've had them, I've never been able to confirm a molt, although I'm pretty sure the big one did at least once.

No scavengers were bothering the "corpses".

I'm running chemistries now. 60g mixed reef. Everyone else is doing fine.

Is it possible they both molted around the same time?

I had one die after 2 years and it was swarmed by my nassarius snails and hermits. My guess it’s a molt.

 

[AGWL]

I already disposed of both of them, so I can't dissect. (Attaching a pic of the big one in all his glory from a few months ago; he was magnificent and huge and really mad at me!)

Chemistries:
SG: 1.023
CA: 440
Mg: 1440
pH: 8.0
Phosphate: 0.32 (using Hanna HI713) (!!)
Alkalinity: 9.1 dKH
Nitrate: 2
Nitrite: 0

 

[AGWL]

UPDATE:

My Sally Lightfoot crab molted (confirmed molt) yesterday and my Coral-Banded Shrimp molted last night, so hoping this was just a mass molting event. Haven't seen either of the emeralds, though.