Crab on Maze Brain

[HandsyLobster]

Hi All,

So I Picked up this maze brain or what I think it is from a local reefer said he had it in his tank for a while and pretty much just gave it to me since its not very colorful. Anyways I dipped it to remove pests and then added it to my tank. I had a bristle worm fall off it. But I was looking closer and there are these teeny tiny crabs living in between the cracks and I have no idea what they are. They don't seem to be bothing it there are like 4-5 of them. Are they bad?

If so what should I do since Coral RX didn't kill them.

Thanks,

 

[ISpeakForTheSeas]

But I was looking closer and there are these teeny tiny crabs living in between the cracks and I have no idea what they are. They don't seem to be bothing it there are like 4-5 of them. Are they bad?

Took me a bit to spot the crab in the pic - they're Gall Crabs (taxonomic family Cryptochiridae):

It has an obligate relationship with the coral - so I doubt the crab would survive long without it.

That said, gall crabs are considered parasites; they shouldn't kill a coral, but they burrow into the skeletons - so if it's a big crab and a small coral, it's a bad combination. If the coral is a decent size, then the crab should just cause a mild deformity; problems generally only arise from algae that grows on the deformed coral skeleton that sticks out through the dead skin.

So, basically, if the coral is big, it'll be fine; if the coral is small, it could die; if the coral is medium-sized, it'll probably be unhappy, but it should survive just fine.

 

[HandsyLobster]

Took me a bit to spot the crab in the pic - they're Gall Crabs (taxonomic family Cryptochiridae):

Thank You,

So the Crab should be fine to be in there?

 

[Reefing102]

Likely a gall crab.

It has an obligate relationship with the coral - so I doubt the crab would survive long without it.

That said, gall crabs are considered parasites; they shouldn't kill a coral, but they burrow into the skeletons - so if it's a big crab and a small coral, it's a bad combination. If the coral is a decent size, then the crab should just cause a mild deformity; problems generally only arise from algae that grows on the deformed coral skeleton that sticks out through the dead skin.

So, basically, if the coral is big, it'll be fine; if the coral is small, it could die; if the coral is medium-sized, it'll probably be unhappy, but it should survive just fine.

Edit: Apparently my phone didn’t update with the most recent responses

 

[ISpeakForTheSeas]

Thank You,

So the Crab should be fine to be in there?

Most likely, yeah.

If they start reproducing, it could be problematic, but as long as more don't start popping up, they should be fine.

I haven't looked into their reproduction enough yet to know if their larvae would even have a chance of surviving in a normal tank, but I'd assume they won't be an issue for you. That said, if they become an issue, the females at least rarely leave their holes (the males are typically free-living, so they leave the holes occasionally), so you should be able to just stab them and get rid of them that way (they definitely can't reproduce without females).

 

[HandsyLobster]

Most likely, yeah.

If they start reproducing, it could be problematic, but as long as more don't start popping up, they should be fine.

I haven't looked into their reproduction enough yet to know if their larvae would even have a chance of surviving in a normal tank, but I'd assume they won't be an issue for you. That said, if they become an issue, the females at least rarely leave their holes (the males are typically free-living, so they leave the holes occasionally), so you should be able to just stab them and get rid of them that way (they definitely can't reproduce without females).

Perfect,

Thank You so much for the help. I was freaking out and can sleep at night now.

 

[taricha]

the number of other organisms that corals grow around and over in the wild is enormous.
(our tank isn't the wild so beware of that analogy, but still - tiny crab in a big brain coral is not a thing I'd get aggressive over.)