Gull crab in Elegance coral? Coral dip didn't work

[Zpmada]

I've had an Australian Elegance coral for 1.5 years and just noticed orange legs inside when the lights go out.

I did a little research and suspect this might be a gall crab.

I tried to do a coral dip with Kent Marine Lugol's solution as per the bottle - 40 drops per 1 gallon in a bucket for 10-15 minutes.

I didn't see any crab come out. I actually can't see the crab anymore so I think it went deeper. Now that the coral is closed I'll have to wait until tomorrow night to check it out.

Does the gall crab need to be removed? Any suggestion? The coral opens large during the day and seems to be my largest coral. I thought it was doing well other than the legs that come out at night when the coral deflates a bit. It's bank in the tank after the coral dip and I see the orange legs again

Thanks

 

[Timfish]

I would leave it personally. Gall crabs use corals for protection not food, they've just figured out how to manipulate skeletal growth. What intrigues me is endoliths in the coral skeleton are very helpful and important parts of the coral holobiont so does the gall crab and it's protective opening improve the simbiosis with improved water exchange.

 

[Zpmada]

I'm amazed that the Elagance Coral seems to be a danger to most other inverts but this crab happily lives inside it. I saw it walking ontop of the coral this morning but I didn't have tweezers. I'll pickup tweezers and be ready next time if it's easy to pick off. I dont want to start digging and damage the coral. It's in a new spot now unless there is more than one hiding.

 

[Vinny Kreyling]

I would follow Tim's advice & just leave it alone.

 

[Zpmada]

Ok, odd that so many people suggest removal. The coral has been doing great for 1.5 years so I'll leave it alone.

I did find this website that suggests the Gall Crab has a symbiotic relationship with the coral. The Gall Crab protects the coral from coral eating starfish and snails and the coral offers the crab shelter
Very neat!

https://okinawanaturephotography.com/gall-crabs-coral-inhabiting-micro-crabs-of-okinawa/