Acro crabs

Jim Z. said:
Trapezia, although larger and more colorful than Tetralia associate with Stylo's, Poci's, and birds nest sps corals.
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Technically, that's not entirely true. For example, Trapezia has been observed to host Acropora Solitaryensis. Although this is not common. The reason why or how Trapezia (or others) select host is still a mystery. It has been suggested that one factor is size of the crab and branch spacing of the host corals. It seems like Trapezia prefer host with dense branching and tight space while Tetralia seems to prefer a slightly more wider spacing.

Jim Z. said:
Red bugs do not do well in Acropora that have resident Tetralia.
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Can you show me a link where this is published?
 
yeah i agree with dzhou i want to see this
but it would be nice if these crabs would keep red bugs and aefw off of our sps corals
 
How do we know if it is a good crab or a bad crab?


I have like 3 of these in my tank. They typically hang out in one of my 2 larger birdsnest.
Looks just like this....

TeddyBear_Crab_by_RedBledVelvet.jpg


I have noticed that the bottom side of these corals are going white? Both they typically hang out in. I assumed from not enuf flow or lack of light as the corals are getting thick? Maybe I have a bad "acro crab" The teddy bear crab mentioned above? It is a little fuzzy for sure. Looks like a small fuzzy emerald crab. I can try to get actual pics.

Here is a picture of the base of one of my birdsnest they frequent!
IMAG0066.jpg
 
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Ok, I can easily pull the 2 corals they hang out in. Anything i should do with them, put them in keep them? Any use for anyone?
 
They probably wouldn't survive without the acro. We still don't know much about their dietary requirement but my guess is they would starve and die. I hate to say this but I would just toss them out or give them to your LFS (as food for other aggressive fish).
 
110galreef said:
All along i thought he was a cool Acro Crab.
Click to expand...

Cymo andreossyi is similar to Tetralia and Trapezia. It will protect and "clean" the host coral. In the wild, it's extremely rare for Cymo andreossyi to kill an acro taking a few polyps or flesh occasionally. They are not considered a pest or predator. However, in our tank (I assume it's due to food) they do considerable damage.
 
I have never seen a study if they eat AEFW, red bugs or planaria so I don't know. My guess would be no.
 
I recently purchased a wild coral that came with one those guys along with a squat lobster. Like you I was excited to see the crab in there and thought the squat lobster to be the pest. ehhhhhhh wrong, other way around! lol The lobster is a cool little guy and live in my fuge where ive only spotted him all of once in the month or so hes been in there! The cymo had left a trail of destruction in the acro though and it looked exactly like what you posted execpt the coral was much more dense that birdnest so it was tougher to see. The scary part is that had I not QTed the coral, I doubt id ever have seen him. I dipped the coral for 12 minutes twice in brightwells coral rx which scattered everything out of the coral EXCEPT the cymo. I didnt even see him for a few days until I put a flashlight on the coral and saw the glow of his eyes! Lesson learned there!

Also, he was VERY hard to get out which led to me having to pull a few of his limbs off in the process. My lfs took him as a snack for triggers...good luck and glad you were able to get this info as it couldve really had you chasin your tail! lol
 
I have both Cymo andreossyi and Trapezia in my systems and neither seem to do any harm. The Trapezia has been in my Sarmentosa for 6 months now and a Cymo andreossyi has been in both of my tanks for the same amount of time. The Cymo andreossyi out grew the acros in a short amount of time and now lives in the porous live rock pieces.

Maybe I am just lucky with the two that I have but I have never seem any damage from the Cymo andreossyi acro crabs.
 
Yeah, ive read and heard similar where they are kinda in a gray area of friend or foe. I litterally followed a trail of dead eaten tissue right to the guy though and once he was removed the coral quickly recovered...hence i lean towards foe.
 
Update to my Cymo's!

Update to my Cymo's!

Ok, so i knew i had 3, have seen them quite often for the last yr. They typically always hang out in one of my 2 lager BN. Most other SPS are still smaller frags with at most a few stalks.

After reading this I go home to get these guys. Sure enuf I can only find 2! So i figure I will get these two quickly. And wait for # 3 to come back around. I ended up involuntarily fragging a nice size 3" section of my BN. Oh well. Got both pretty easily. About 3 hrs later #3 Cymo shows up in the other corals. Get him out w/o issue.

Here are what I have. They are in my overflow(external c2c) for now. I did give them a few pieces of fish food! :beer: I may throw in my frag tank for a bit and keep close eye on them. Maybe they can be ok?? Easy to catch and remove in there if needed.
IMAG0383.jpg



All 3
IMAG0395.jpg


They really haven't done ALOT of damage but enuf that they need out and have to watch closely.
 
I feel that especially a frag tank, wouldnt be a good home for them. I large colony that wont miss small sections at a time in a stable tank shouldnt be an issue of live or die to the coral, but my thoughts were, why stress the coral and lose chunks of it for protection against what? Our systems after being dipped and QTed(not all of us I know) arent exactly teaming with coral predators...sure theyd be great for when you stir up some grundge in the tank or do too large a WC causing the corals to secrete their slime. I know the cymo I had just nuummm nummmed that stuff right up! lol

If it were me, Id offer them to those that feel they are harmless and are willing to take the chances. Frags have enough to deal with already!
 
Heck, if youve got them in your overflow, does it get any light in there? If so, chuck a few larger branches of your BN in there and have a little biotope! Im all for having another thing to look at! Just toss some grub in there for them on occasion. That should allow you to make a decision one way or the other on whether they are a plus or a minus in your own eyes!
 
That is pretty much what I have done thus far. The overflow get some light. It is like 30"L x 6" H x 4.5"W. I put some of the dead BN branches in there along with some of the pieces I acidentaly fragged. I think there is enuf light to support the frags for a short time as long as lower light corals like the BN.

I can give that a go too.
 
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