Hitchhickers

[Enduring_Aquatics]

I just bought this little birdnest colony. Has I was dipping it I noticed there was three crabs one bigger one, one medium, and a really smaller one I got them out but I would like to know if they are good for the tank or not. Im new here and new to saltwater just started one a couple months ago so I have no idea what these crabs are.

 

[Jtuvey]

Looks like an Emerald Crab. They are great part of your clean up crew. They eat algae and left over bits of food. What size of tank do you have? Three might be to many for your tank.

 

[Rjukan]

Idk, it doesn't look like an emerald crab to me.
Take a look at this article, maybe something in there looks similar..

An introduction to coral crabs, good and bad | Reef Builders | The Reef and Saltwater Aquarium Blog

There is surprisingly little information specifically about coral crabs in aquaria. Every now and then some hitchhikers arrive on our aquacultured and wild corals and we are able to gain a bit more…

reefbuilders.com

 

[CrimsonTide]

Do all 3 look like this one?

 

[ISpeakForTheSeas]

I just bought this little birdnest colony. Has I was dipping it I noticed there was three crabs one bigger one, one medium, and a really smaller one I got them out but I would like to know if they are good for the tank or not. Im new here and new to saltwater just started one a couple months ago so I have no idea what these crabs are.

Can you get some pictures under brighter, white light?

A top-down shot like this is great, and a pic of the crab's face and claws would be useful too.

 

[Enduring_Aquatics]

Can you get some pictures under brighter, white light?

A top-down shot like this is great, and a pic of the crab's face and claws would be useful too.

 

[CrimsonTide]

Do all 3 look like this one?

 

[Enduring_Aquatics]

Do all 3 look like this one?

Yes just smaller. The smallest one died

 

[Uncle99]

Most crabs are trouble.
A post today described a emarald lunching on a leather.
I take no risk at all.

 

[CrimsonTide]

Yes just smaller. The smallest one died

These don't look like normal emerald crabs. There are crabs that love in acropora that are reef safe. I'm however not versed enough to say what this one is.

 

[CrimsonTide]

Hopefully someone can see this and give e a better answer.

 

[Enduring_Aquatics]

Hopefully someone can see this and give e a better answer.

thanks i didnt think they was emerald crabs my lfs sells them all the time and they dont look like them

 

[CrimsonTide]

thanks i didnt think they was emerald crabs my lfs sells them all the time and they dont look like them

I would say they're probably some type of crab that lives in acropora though. I just can't say if they are good or not. If they're good then you should keep them though bc thats a cool symbiotic relationship to have in your tank.

 

[Enduring_Aquatics]

I would say they're probably some type of crab that lives in acropora though. I just can't say if they are good or not. If they're good then you should keep them though bc thats a cool symbiotic relationship to have in your tank.

yeah thats the thing no one can tell me for certain if they are good or bad. ive read some articles saying they are good and some say they are bad for a reef tank

 

[ISpeakForTheSeas]

Can you get a pic like this one but brighter, and a pic like the new one you posted but under white light instead of blue?

Shining a flashlight on the critter can work in a pinch to provide the brightness and white lighting.

 

[Enduring_Aquatics]

Can you get a pic like this one but brighter, and a pic like the new one you posted but under white light instead of blue?

Shining a flashlight on the critter can work in a pinch to provide the brightness and white lighting.

that was a white light for the new picture they are in a quarantine tank that i just threw together for those crabs cause i dont want them in my tank

 

[ISpeakForTheSeas]

that was a white light for the new picture they are in a quarantine tank that i just threw together for those crabs cause i dont want them in my tank

Yeah, try shining a flashlight on it and getting a top-down pic - crabs like this can require really clear pics for an ID.

That said, I can tell you it's not a typical Acro/Coral Crab (Trapezia, Tetralia, and Cymo species) - so it's most likely not reef safe.

 

[Enduring_Aquatics]

Yeah, try shining a flashlight on it and getting a top-down pic - crabs like this can require really clear pics for an ID.

That said, I can tell you it's not a typical Acro/Coral Crab (Trapezia, Tetralia, and Cymo species) - so it's most likely not reef safe.

 

[Mechano]

Does the claws look like they have flat tips on it? If yes, it’s likely some sort of Mithrax crab (emerald crab)

If the crabs have pointy claws, I’d say avoid putting in your tank.
Years ago (15 yrs) I had a Xanthid crab that had a similar body with the blotches. You definitely do not want it in your system…everything is potential food to them.

It’s really hard to make it out though with the pics you have taken and shared

 

[Enduring_Aquatics]

Does the claws look like they have flat tips on it? If yes, it’s likely some sort of Mithrax crab (emerald crab)

If the crabs have pointy claws, I’d say avoid putting in your tank.
Years ago (15 yrs) I had a Xanthid crab that had a similar body with the blotches. You definitely do not want it in your system…everything is potential food to them.

It’s really hard to make it out though with the pics you have taken and shared

the claws are pointed. the legs are hairy they have black dots on their brownish colored bodies