Commensal Crabs - Love 'em or hate 'em

[Mike&Terry]

How do you feel about them?

We have quite a few commensal crabs in our coral colonies and have never had any issues with them - including the blue eyed Cymo andreossyi who has resided in one of our A. hyacinthus colonies for a number of years now. The colony started out small, but has thrived over the years with the crab in it and is so large, that we have to trim it back on a regular basis. It is hard to get a good pic of him as he pretty much stays in his condo:


Here's a pic of the colony he resides in:


Here's a pic of one of the many Trapezia crabs we have:


And an FTS taken earlier today:


Many years ago, we did remove one crab that came in as a hitchhiker on a small stylophora colony. It obviously was not a commensal crab and left a path of munched polyps on several corals in it's wake in a matter of days, LOL. Not sure of the species, but we were told it was commonly referred to as a gorilla crab. We'll have to see if we can hunt down a pic.

-M&T

 

[ritter6788]

I had a few here and there. They've always disappeared over time. They have always just vanished on me. I had a really cool pink one that came in a pink Pocillapora colony that was there for months and then one day it was gone. Love your pics!

 

[Russellaqua]

Love them. The corals like them, they like the corals, and I like that. :bigsmile: Can't complain about beneficial hitchhikers.

 

[revhtree]

I love them and awesome!

 

[Aquaph8]

The small critters are what make our tanks so much fun to watch, love em.

 

[nicks387]

I love them, I also have 2 of the blue eyed ones as pictured and they cause no visible damage to the coloies that house them.

 

[droblack]

I don't like crabs except for on "all you can eat" night, but make exceptions for acro crabs and the like. Cool little inhabitants. The ones with the black band across the front, like a mask, are really cool.

 

[3Twinklets]

I love them and those are some great photos!

 

[Mike&Terry]

Thanks for all the replies everyone!

I love them, I also have 2 of the blue eyed ones as pictured and they cause no visible damage to the colonies that house them.

That is good to hear!

Anyone had a bad experience with them?

 

[Dowtish]

I just got 2 mini colonies of millepora from a friend, and was planning on chopping them up to raffle off free frags for our club. There was a crab in one of them, and it seemed to inhibit polyp extension compared to the other one. I have since chopped them up, and left the base of it, and I'm sure the little guy is wondering what happened to all his sweet protective branches. Maybe he'll stay there or move somewhere else???

Just wondering if my halichoeres wrasses will take advantage of that if and when he tries to travel.

 

[kmaintl]

I've never seen one???

 

[_Alex_]

we have electric blue hermit crabs that have not caused any problems have 4 or 5 at the moment in varying sizes from maybe a half inch close to a inch and a half..
here is a older picture of our largest one on one of our cristmas tree rocks, have nevre seen any of them bother any coral. we have lps, sps , polps and shrooms also a few gorganions

also have halloween crab that is basicly the same only orange and black

 

[Troylee]

Thanks for all the replies everyone!


That is good to hear!

Anyone had a bad experience with them?

I had a blue eyed one that lived in a Millie and ate all the polyps off a single branch... Never affected the rest of the colony just a single stem in the back so I removed it...

 

[ingtar_shinowa]

I have a Cymo in my rose colored Milliepora that is directing branch growth. He came in on a yellow efflo frag and grew about 600% in the millie. I am letting him live in my colony hoping he stays good.

I also have 2 Trapezia in a Valida colony.

 

[Mike&Terry]

I have a Cymo in my rose colored Milliepora that is directing branch growth. He came in on a yellow efflo frag and grew about 600% in the millie. I am letting him live in my colony hoping he stays good.

I also have 2 Trapezia in a Valida colony.

Awesome! Our cymo has done the same - making a nice little condo for himself, LOL. If you look close, you can see him sitting in there:


-M&T

 

[Mike&Terry]

we have electric blue hermit crabs that have not caused any problems have 4 or 5 at the moment in varying sizes from maybe a half inch close to a inch and a half..
here is a older picture of our largest one on one of our cristmas tree rocks, have nevre seen any of them bother any coral. we have lps, sps , polps and shrooms also a few gorganions

also have halloween crab that is basicly the same only orange and black

Alex, thanks for sharing your experience and great pic!

 

[ingtar_shinowa]

I love your gus tank. My alk plumited last month and it looks like I might lose my valida acro. Really nice peices, and I love the crabs. Have you ever seen a Trapizia ​in a birdnest?

 

[Mike&Terry]

I love your gus tank. My alk plumited last month and it looks like I might lose my valida acro. Really nice peices, and I love the crabs. Have you ever seen a Trapizia ​in a birdnest?

Thank you! Sorry to hear about your alk swing and we hope you are able to save your valida colony. We have trapezia crabs and I've seen them "visit" our seriatopora colonies, but for the most part, they tend to hang out in our pocillopora and stylophora colonies.


Anyone else?

-M&T

 

[Aquaph8]

I had a trapizia that bounced between my bird nests, then one day he was gone. No idea what happened to him.