Emerald crab and corals

[Goldberg]

Hello everyone,

I would like to ask for your experience with emerald crab.
All the shops around saying it is reef safe, yet online many suggesting it maybe not that safe. have you tried keeping any? did it turn on your corals or maybe clams ?

Mostly its used for bubble algae, if you got it at one point of time, did you find any other way to combat this type of algae?

Thanks,

 

[Lavey29]

Pithos crabs better for bubble algae and reef safe

 

[Sump Crab]

I have had probably close to 50 green and red mithrax crabs (emerald crabs) over the past 20 years and only ever had 1 eat coral. It was a green female and I caught her eating acans. IME the odds are that they will not eat coral.

 

[Goldberg]

I have had probably close to 50 green and red mithrax crabs (emerald crabs) over the past 20 years and only ever had 1 eat coral. It was a green female and I caught her eating acans. IME the odds are that they will not eat coral.

Thanks for sharing your experience, 20 years is a long time in the hobby.
I was reading online to get a female for more safety but seems crab is a crab despite the gender.

 

[Goldberg]

Pithos crabs better for bubble algae and reef safe

Thanks, i tried to search for it, doesn't seem existed around here. Pithos look nice though

 

[mues]

I haven't had an issue with my emeralds eating coral

 

[Lavey29]

Thanks, i tried to search for it, doesn't seem existed around here. Pithos look nice though

Pithos Crab

www.saltybottomreefcompany.com

 

[kevgib67]

Pithos crabs better for bubble algae and reef safe

^ this! But I’ve always had emeralds and never experienced a problem.

 

[JFinlay]

Purchased 4 emeralds total and every single one ate my SPS, mainly birdsnest, then they started to migrate to the hammers, at which point they all got thrown in the fuge. I am 100% certain they were eating them, watched them rip the flesh right off the birdsnest until it was just skeleton, and they would always stay around it at night. Didn't touch my bubble algae!

 

[Doctorgori]

Purchased 4 emeralds total and every single one ate my SPS, mainly birdsnest, then they started to migrate to the hammers, at which point they all got thrown in the fuge. I am 100% certain they were eating them, watched them rip the flesh right off the birdsnest until it was just skeleton, and they would always stay around it at night. Didn't touch my bubble algae!

while my experience is contrary to that, this post is important data as there must be a as yet undiscovered variable here. I’d love to know what the difference is here: could it be a miss I.D or diet or coral type…
Not sure how to parse that out, but I believe you

 

[19Mateo83]

I Have two in my 50 gallon and so far one of them likes to hang out underneath a green bird‘s nest and the other one likes to hang out near my Milka Stylo. They have not picked any polyps yet, but I have been keeping an eye on them. I did notice one eating the shed from a neon green toadstool, but he was not messing with the actual toadstool. Personally, I am still up in the air on them and ready to snatch them out, and put them in my sump if need be. I have been looking for pithos crabs locally and so far, I have only seen one and it was huge. Is this normal size for a pithos?

 

[Sharkbait19]

Thanks for sharing your experience, 20 years is a long time in the hobby.
I was reading online to get a female for more safety but seems crab is a crab despite the gender.

Females don’t get as large and have smaller claws, which tends to make them a bit safer.
I’ve only had one crab go after corals (and a brittle star). The rest of mine have been perfect.
I also do like pithos a lot - I have both emeralds and pithos in my reef tank and they do a great (enough) job with bubble algae.

I Have two in my 50 gallon and so far one of them likes to hang out underneath a green bird‘s nest and the other one likes to hang out near my Milka Stylo. They have not picked any polyps yet, but I have been keeping an eye on them. I did notice one eating the shed from a neon green toadstool, but he was not messing with the actual toadstool. Personally, I am still up in the air on them and ready to snatch them out, and put them in my sump if need be. I have been looking for pithos crabs locally and so far, I have only seen one and it was huge. Is this normal size for a pithos?

They get pretty big. When I got my first one from reefcleaners I was expecting it to be emerald size, but it came in easily 2.5-3 inches from leg to leg.

 

[exnisstech]

I keep them. I just added 6 more to this tank. I've never had them eat coral. I added a few pitho a while back but they mostly stay under then rocks and try to reach out and grab food floating by. The emeralds are always actively eating algae. I supposed the pithos may be coming out at night

 

[aquaman67]

I just added two to my tank for the first time a few days ago.

I haven’t seen them since.

 

[smoothie7]

I've never had a problem with emerald crabs and enjoy watching them in my tanks.

 

[FishTruck]

I have had emerald crabs on and off for years. Just don't buy so many that they run out of food.

Bubble algae... resorted to manual removal, disposal of colonies too far gone, emerald crabs, and vibrant (algaecide) and eradicated from a display after a two year battle.

 

[Cheezle]

I added 2 emeralds to my tank a few weeks back and they've been model citizens. They help eat a lot of the bubble algae that builds up around my clam all while never bothering the clam itself.

 

[JFinlay]

while my experience is contrary to that, this post is important data as there must be a as yet undiscovered variable here. I’d love to know what the difference is here: could it be a miss I.D or diet or coral type…
Not sure how to parse that out, but I believe you

I agree, I couldn't figure out a rhyme or reason and really wanted them to work as my bubble algae is getting out of hand. I purchased 2 each from 2 different LFS, all but 1 of them I caught in the act of eating a coral at night time.

I highly suggest if you guys haven't watching their activity at night, they're much more brazen. Will go across the whole tank

 

[Goldberg]

my update wasnt as pleasent as some who had good experience wit them. I wanted to give one the chance and added him in the tank, for two days he was after the zoas eating them. I think its just a luck for me, just got him returned to the store

 

[jimmers]

Hello everyone,

I would like to ask for your experience with emerald crab.
All the shops around saying it is reef safe, yet online many suggesting it maybe not that safe. have you tried keeping any? did it turn on your corals or maybe clams ?

Mostly its used for bubble algae, if you got it at one point of time, did you find any other way to combat this type of algae?

Thanks,

Great for bubble algae. 90% reef safe. If you have small frags I would keep a close eye.