Open Brain Coral Pest in Skeleton?

[mynameisnick4]

I have (what I think is, correct me if I am wrong) an open brain coral with a few suspicions holes in it's base/skeleton. For the past few weeks it hasn't been opened nearly as big as it used to be (I have had it for about a month and a half.) I pulled it out to reposition it and noticed these two holes with what looks like something in them. Anyone know if this is a pest or if there is something else going on? Here a few pictures of the holes in question plus one of the coral normally:

 

[J.D.]

Looks like Gorilla Crab holes. If you do a search, there are a lot of writeups on them.

 

[mynameisnick4]

Looks like Gorilla Crab holes. If you do a search, there are a lot of writeups on them.

I came across gall crabs when I was trying to research this but their holes looked more round but never heard of gorilla crabs. I did a quick search on them and they look pretty big compared to these holes.

 

[cpoynter]

Could be Boring Bivalves. I just removed two from a button scoly with a dremel & cutting wheel. Coral was happier after the initial shock.

 

[ISpeakForTheSeas]

It does look like a bivalve in there if you zoom in on that first pic.

 

[mynameisnick4]

Could be Boring Bivalves. I just removed two from a button scoly with a dremel & cutting wheel. Coral was happier after the initial shock.

It does look like a bivalve in there if you zoom in on that first pic.

If they are bivalves, are they something that needs removed? Will dips kill it? I took another look to see if I could grab whatever it is with a pair of needle nose tweezers but couldn't grab it. When you first pull it out of the water, it is flush with the outside of the coral. When you try to grab it, you just end up pushing it into the hole which is surprisingly deep:

 

[J.D.]

Looks like Gorilla Crab holes. If you do a search, there are a lot of writeups on them.

Ment Gall Crab

 

[BranchingHammer]

Looks more like a bivalve to me.

 

[ISpeakForTheSeas]

If they are bivalves, are they something that needs removed? Will dips kill it?

I don’t know if dips would kill it or not. With regards to removal, they sound similar to Coral Boring Barnacles, where (unless they’re in an incredibly bad location in the coral) they’re technically harmless, but they may stress the coral a bit and cause some deformed growth patterns as the coral grows around it and its tunnel.

So, removal is really up to you - it most likely won’t kill anything, but it may stress the coral for a time and cause some unusual growth.

 

[mynameisnick4]

I don’t know if dips would kill it or not. With regards to removal, they sound similar to Coral Boring Barnacles, where (unless they’re in an incredibly bad location in the coral) they’re technically harmless, but they may stress the coral a bit and cause some deformed growth patterns as the coral grows around it and its tunnel.

So, removal is really up to you - it most likely won’t kill anything, but it may stress the coral for a time and cause some unusual growth.

I guess I will monitor it for now. Going off of my first attempt to remove whatever it is, there is a good chance I would damage the skeleton further trying to dig it out.

 

[cpoynter]

Hopefully someone will correct me if I’m wrong, but my understanding is that the barnacles that live in coral don’t typically survive that long in aquariums. If it is a barnacle, you’ll notice it fanning the water when it feeds. If it looks like there is a siphon extending from the hole(s), it’s probably a bivalve in which case it can, at least, irritate the coral, and at worst, damage the polyp. In order to remove the bivalve(s), you’ll need to cut the skeleton away. Ideally you’d use a band saw appropriate for coral, or you could use a dremel with a cutting wheel. Either way, you’re going to damage the coral skeleton on the bottom, which is fine. The think to keep in mind is heat from the friction. You need to cut a little at a time, and dip the skeleton in water to keep it from getting too hot.

 

[ISpeakForTheSeas]

Hopefully someone will correct me if I’m wrong, but my understanding is that the barnacles that live in coral don’t typically survive that long in aquariums. If it is a barnacle, you’ll notice it fanning the water when it feeds. If it looks like there is a siphon extending from the hole(s), it’s probably a bivalve in which case it can, at least, irritate the coral, and at worst, damage the polyp. In order to remove the bivalve(s), you’ll need to cut the skeleton away. Ideally you’d use a band saw appropriate for coral, or you could use a dremel with a cutting wheel. Either way, you’re going to damage the coral skeleton on the bottom, which is fine. The think to keep in mind is heat from the friction. You need to cut a little at a time, and dip the skeleton in water to keep it from getting too hot.

Yeah, this looks like a bivalve to me, not a barnacle. Most barnacles don't survive very long in our aquariums, but I've heard the coral-boring ones tend to last a while longer (two people in thread linked below reported theirs living for at least a year).

Barnacles

To dip or not to dip. I would hate to kill these 2 barnacles. I’ve heard they will eventually die in the home aquarium, but I would hate to be the one to do it purposely. Will they eventually harm my coral? Side note: It was nighttime with the lights off, so it had started to close up. I turned...

www.reef2reef.com

My understanding is that - bivalve or barnacle - they're typically harmless (might cause some irritation and/or deformation, but they shouldn't do too much damage and/or kill the coral), but sometimes they're in just the right spot to do some damage.

 

[Tired]

Oh, that's definitely a bivalve in there.

I would leave it alone and look for other reasons why the coral might not be doing well. This guy's pretty unlikely to be the problem.