Friend or Foe

8 May 2007
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Removed fromm some new acro (this weekend) Acro was showing tissue damage close to base. Dispatched to Valhalla





the first one looks like a normal acro crab to me
Hi Sunburst, i have had the little black and white one also cause trouble on my acro's. I am not that familiar with acro crabs and dont know the good from the bad so i removed all of them.
yeah the top one looks exactly like the one i got!!

never had hassle with him
Pic 1 harmless, Pic 2 harmful. Actually breaks off calcites and eats them!
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They pretty cute crabs though.
Pic 1 harmfull, Pic 2 harmful. Actually breaks off calcites and eats them!

so what you saying then is i need to get him my acro? he's been there for over a year and no damage?
There are some crabs that have a symbiosis with corals, and therefore live peacefully with them.
yeah i am awares, but mine is exactly the same as the one in pic 1
Well if he hasn't done anything funny yet, why would he start now?

I'd keep him.
lol does anyone have an id for that crap?
Pic 1 harmfull, Pic 2 harmful. Actually breaks off calcites and eats them!

Thank you Mr Irie Ivan Sir.
Your comment certainly saved a coraL.
On Saturday (after loosing to the bulls) i was staring into my tank,... once again,... easing the pain... swallowing gulps of beer; when i noticed two acro growth tips that looked as though they had been crushed.
I immediately thought that the only fish with the jaw power to do that was the Fox Face. Since then i have been scheming of a way to ditch him and maybe recover some of my expense....Step 1 buy fish trap... bought fish trap ... step two.... too lazy...rather check if any body has id my crabs on MASA

And thats when i read "and eats them"

Acro Specimen removed.... This ugly b......found and dispatched. I tried to take a pic of the damaged tip but came out a little overexposed.


This is the third crab of the same genus that i have found.... with a wake of damage. They are very difficult to see as they only come out to feed at night and hunker low down in the branches during the day.
Siht just re read my post, really sorry guys: pic1: harmless, pic 2 harmfull

That is exactly the way they feed, by "crushing" a polyp/calcite and eating it.
After my latest episode with a broken lense/uv filter i discovered this black crab feeding on the resulting algae growth. My attitude towards crabs in general has become a lot more accommodating, but i am still nervous that there maybe those that should be cautioned against. Is this one?


Something setting off my spidey sense...


How long have you had that piece of Acro??

Alan, doesn't green basal areas of last acro pictures remind you of something ?

LOOKS like the invasive, parasitic, fatal(to coral) Ostreobium algae spp.
AKA Green Boring alga

It's down right sneaky in it's onslaught

"boring=unexciting", it AIN'T!!

It's contagious in aquarium perspective.

I hope I'm guilty of misdiagnosis.

Any case, it's best to fragment into healthy tissue.
THEN biopsy necrosed area.
If in cross-section it's green, Ostreobium is confirmed as pathogen!

Don't want you to incur losses, or incite your wrath ( Valhalla nogal!)

Contact me if you'd like directions/further action options.

Good Luck routing out all invaders.
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