Emerald crab mystery

AGWL · Mar 25, 2023

I had an emerald crab, named "Grump". He was, in the words of the LFS, the biggest one they had seen. He was awesome. He died about a month ago. At first I thought it was just a molt, but the "body" looked pretty solid, no visible split, and, also, I breed freshwater shrimp and they molt all the time, so I'm used to exos. Or so I thought.

After Grump passed, I got a pitho crab who is also awesome. And about 3 weeks ago, I got 3 emeralds from the same LFS. They were much, much smaller than Grump. Very cute.

Yesterday, I found one of the little ones belly up. Again, didn't particularly look like a molt to me. Sad, but these things happen.

Today, during a water change, I was counting crabs. One tiny emerald. Two tiny emerald. Big pitho. And....who the heck is THAT?

Massive emerald. Huge. Big claws. As near as I can remember, probably the size Grump was, although I don't remember his/her claws being that big.

I'm so confused. It's only a 55-gallon tank and if Grump did just molt, where has he been all this time? Do/can they hide for that long? Or did my tiny emerald molt into a huge emerald? Who died? Did anyone die?

What is even happening here? (And I have more emeralds arriving Tuesday. Yikes!)

Stomatopods17 · Mar 25, 2023

You'd be surprise how humongous they get after 1 molt.

I had a crab go from a golf ball to the size of a base ball once (shameface crab). It doesn't even seem physically possible to grow that much but one of the little ones turning huge overnight is indeed possible.

Davem24 · Mar 25, 2023

Is that many emeralds in a 55 possible? Not being sarcastic seriously asking. What are they eating? I've only kept emeralds for bubble algae.

Stomatopods17 · Mar 25, 2023

Davem24 said:
Is that many emeralds in a 55 possible? Not being sarcastic seriously asking. What are they eating? I've only kept emeralds for bubble algae.

I don't think there's much of a limit to how many you can keep.

As long as there's space you minimize fighting between them, food wise they'll eat pretty much anything. We keep them for bubble control but will easily survive off whatever food you toss in for the fish.

Sink_or_Swim · Mar 25, 2023

AGWL said:
I had an emerald crab, named "Grump". He was, in the words of the LFS, the biggest one they had seen. He was awesome. He died about a month ago. At first I thought it was just a molt, but the "body" looked pretty solid, no visible split, and, also, I breed freshwater shrimp and they molt all the time, so I'm used to exos. Or so I thought.

After Grump passed, I got a pitho crab who is also awesome. And about 3 weeks ago, I got 3 emeralds from the same LFS. They were much, much smaller than Grump. Very cute.

Yesterday, I found one of the little ones belly up. Again, didn't particularly look like a molt to me. Sad, but these things happen.

Today, during a water change, I was counting crabs. One tiny emerald. Two tiny emerald. Big pitho. And....who the heck is THAT?

Massive emerald. Huge. Big claws. As near as I can remember, probably the size Grump was, although I don't remember his/her claws being that big.

I'm so confused. It's only a 55-gallon tank and if Grump did just molt, where has he been all this time? Do/can they hide for that long? Or did my tiny emerald molt into a huge emerald? Who died? Did anyone die?

What is even happening here? (And I have more emeralds arriving Tuesday. Yikes!)

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Don't they typically hide for a while right after molting until their body hardens up some, to protect themselves, or is it just shrimp that do that? Maybe he was just playing a really good game of hide and seek?

AGWL · Mar 25, 2023

Sink_or_Swim said:
Don't they typically hide for a while right after molting until their body hardens up some, to protect themselves, or is it just shrimp that do that? Maybe he was just playing a really good game of hide and seek?

I wouldn't have thought they'd hide for a month. It's not that big of a tank. Even when my pitho buries himself, I can usually find him pretty easily. I really have no idea.

AGWL · Mar 25, 2023

Davem24 said:
Is that many emeralds in a 55 possible? Not being sarcastic seriously asking. What are they eating? I've only kept emeralds for bubble algae.

I've got a massive cyano bloom right now, and they're munching on that (barely making a dent in it). They'll also come begging when I'm feeding the other critters; they really love the R.O.E. and ReefCandy.

C4ctus99 · Mar 25, 2023

My emerald crab disappears for sometimes a week or more, then randomly reappears. His name is fish bait

Davem24 · Mar 26, 2023

AGWL said:
I've got a massive cyano bloom right now, and they're munching on that (barely making a dent in it). They'll also come begging when I'm feeding the other critters; they really love the R.O.E. and ReefCandy.

They eat cyano? Interesting. My nano tank has a cyano and bubble outbreak because it got neglected during my 75gal build. Once I get the nitrates back to reasonable levels I'm going to add some emeralds.

kjkszpj9 · Apr 1, 2023

Bro each of his claws are bigger than his body holy hell hes huge.

blaxsun · Apr 1, 2023

Could be your original crab. They can hide for a while after molting; it's also possible that while he was hiding he found a readily-available food source...

Sink_or_Swim · Apr 4, 2023

AGWL said:
I wouldn't have thought they'd hide for a month. It's not that big of a tank. Even when my pitho buries himself, I can usually find him pretty easily. I really have no idea.

Hmmm, it's a mystery! I know when my first 2 died (old age I believe), I found the carcasses pretty easily... so maybe he's alive and only coming out at night or something, making you worry for no reason, lol. Who knows!