Emerald crab spontaneously died?

[moose11]

Hey guys,

so I’ve had an emerald crab for about a month. He looked healthy all the way up to today. Typically I give him a small peice of nori here and there as a treat. He grabs it out of tweezers and munches down.

today I gave him his nori treat and he was hanging out in his favorite spot. He grabbed the nori and mowed it down like usual, and then 5 minutes later he was upside down on the sand. His color was vivid green like he was supposed to be when I fed him, but he had turned a light brown color and looked like he just fell off the rock right where I had fed him.

water params are all good

ammonia 0
Nitrite 0
Calc 440
Phos 0 (hard to tell with the test I’m using but there was no tinge of blue to the water at all that I had tested)
Nitrate 5
Ph 8.2
Salinity 1.025
Alk 9.1 (typically varies from 9-9.1)
I don’t have mg test yet
Temp 78

all other inverts and fish are doing just fine.

He wasn’t overly old, he was fairly small when I got him and no where near the size of some emeralds I’ve seen. Any idea why that could be? Could the Moro be tainted? It’s the same sheet I’ve been feeding him for weeks now in little bits, the conch and tang have been eating it too? I’m genuinely at a loss how he went from happy healthy and chowing down to dead in a matter of minutes. The only thing that changed was I added probably 1/4 to 1/3 gallon of rodi water to help with evaporation in the time between feeding and death, but I added it slowly and the temp didn’t fluctuate.

Thanks so much in advance! I’m super worried about my fish and the rest of my tank nuking for some odd reason that I can’t foresee here since he died so fast out of the blue.

 

[homer1475]

Sure it wasn't a molt?

 

[moose11]

Sure it wasn't a molt?

I guess I’ve never seen a molt before but it sure looks like the whole crab, I’ll add a photo and see what you think? I also can’t find him anywhere as I searched and searched and he’s not in any of his usual places

 

[moose11]

I guess I’ve never seen a molt before but it sure looks like the whole crab, I’ll add a photo and see what you think? I also can’t find him anywhere as I searched and searched and he’s not in any of his usual places

It’s more green now than what it was inside of the tank before I removed it, it was way more brown, not sure how that’s possible

 

[homer1475]

Can't tell from the pic, but one sure fire way to tell if it's a molt...

Is there a "trap door" on the rear of the shell open?

When they molt, they literally crawl out of their old exoskeleton and an entire body is left behind.

 

[moose11]

Can't tell from the pic, but one sure fire way to tell if it's a molt...

Is there a "trap door" on the rear of the shell open?

When they molt, they literally crawl out of their old exoskeleton and an entire body is left behind.

I’m dumb I see it now, there’s a hole under where his mouth would be on the front that’s quite large and there’s nothing inside. It didn’t appear that way when I first removed it. My apologies, I guess I over panicked. This is my first shot at a reef and I’m still fairly new to this game

 

[moose11]

I’m dumb I see it now, there’s a hole under where his mouth would be on the front that’s quite large and there’s nothing inside. It didn’t appear that way when I first removed it. My apologies, I guess I over panicked. This is my first shot at a reef and I’m still fairly new to this game

Can't tell from the pic, but one sure fire way to tell if it's a molt...

Is there a "trap door" on the rear of the shell open?

When they molt, they literally crawl out of their old exoskeleton and an entire body is left behind.

thanks for the help lol, I feel silly now but I also feel much better

 

[homer1475]

Yup thats a molt!

Don't be surprised if you don't see the crab for a couple days. They tend to hide while their new skeleton hardens up(while they are soft, they are very easy to being eaten).

 

[moose11]

Yup thats a molt!

Don't be surprised if you don't see the crab for a couple days. They tend to hide while their new skeleton hardens up(while they are soft, they are very easy to being eaten).

Phew. Thanks again so much. I really appreciate the quick reply!

 

[Tired]

Oh, don't worry, people get fooled by molts all the time. That is impressively fast after eating, though- speedy guy!

 

[moose11]

Oh, don't worry, people get fooled by molts all the time. That is impressively fast after eating, though- speedy guy!

That’s what I was so confused about! I can’t believe it could happen that quickly. And to make matters worse my significant other decided to buy a “designer” clownfish the other day so I’m even more on edge now than ever. I swore I’d never have a fish that was that expensive and when I thought something died I thought the whole tank was a goner

 

[moose11]

That’s what I was so confused about! I can’t believe it could happen that quickly. And to make matters worse my significant other decided to buy a “designer” clownfish the other day so I’m even more on edge now than ever. I swore I’d never have a fish that was that expensive and when I thought something died I thought the whole tank was a goner

Here’s of pic of the fish she just had to have for your troubles lol

 

[homer1475]

Longfin clown, their a couple benjamins.

 

[kevgib67]

Molts look identical to the original molt. After they molt they go into hiding for a couple days while the shell hardens. This is when they are most vulnerable to predators.

 

[Tired]

Worth noting that animals do sometimes die of things other than "entire tank is now inhospitable to life". You might have an animal that's already sick, or one that's especially sensitive to a parameter other creatures in the tank don't much care about. A dead critter is cause for investigation, not for panic.