crab hitchhiker's in the corals!!

[commwire]

Hi All,

Just a quick question?? I have purchased a couple of new acro's since I acquired my new MH lighting. The corals have been in the tank about a month now and are doing great...however I see little pinchers sticking out of the corals when I feed. And I can see they are about 4 baby crabs between the two living inside the corals.I want to get rid of them...(I will put them in the refugium) and I have tried but they are to quick for me. So does anybody have any advice for their removal...without me hurting the corals. They will destroy my 3 year old DSB when they get a little older.

Thanks in advance!!

~Carmen

[reefhorse]

These may be acro crabs which are very beneficial. Iahve some which I like very much. Here is a link with some more info
http://www.reefed.edu.au/explorer/downloads/Pratchett_crab.pdf
Sincerely,
John

[EricHugo]

They are almost certainly associated symbiotic crabs - do not remove them.

[commwire]

Thanks...Eric and John..the crabs get to stay :) . When I see pinchers..I get very nervous. I had a couple of crabs that came in on the live rocks a couple of years back and they quickly depleated just about all of the critters in the DBS. ...until I got them out...hence my concern
Thanks Again!!!

~Carmen

[commwire]

Eric, I just wanted you to know that I use your coral receipe and it is wonderful...it has done wonders for my tank inhabitiants. I believe that between your food and the MH lighting.. makes all the difference..My corals and fish are really just breathtaking..lots of color!!

THANKS!!

~Carmen

[SeaStar]

Eric, you sound very stern in your response not to remove the crabs. I assume they help their coral host by eating parasites off the colony and they in turn receive protection from the colony. If a crab was removed from it's host would the host be anymore susceptible to disease than a colony that never acquired a symbiont. Another-words does a colony become reliant upon a symbiotic crab or shrimp to the point where it loses some of it's natural defenses.
Also if available foods where to become scarce, such as is most likely the case in our systems (compared to the wild), could a symbiotic crab turn on its host and start eating polyps.

[EricHugo]

Carmen: good news!

SeaStar

>>ric, you sound very stern in your response not to remove the crabs. I assume they help their coral host by eating parasites off the colony and they in turn receive protection from the colony. <<

Well, different crabs do different things. Some ward off coral predators, some groom the mucus of potential pathogens and debris, and some do little tonothing at all...some even eat a little coral tissue....not mcuh and not many.

>>If a crab was removed from it's host would the host be anymore susceptible to disease than a colony that never acquired a symbiont.<<

Yes, that has been found to be the case.

>> Another-words does a colony become reliant upon a symbiotic crab or shrimp to the point where it loses some of it's natural defenses. <<

Never been studied, but unlikely.

>>Also if available foods where to become scarce, such as is most likely the case in our systems (compared to the wild), could a symbiotic crab turn on its host and start eating polyps.<<

Depends onthe crab, but again, unikely.