Help! Crab Identification needed

[JPSwanHome]

I bought a Millepora last week. It looked great for about two days. Then it started regressing. The last couple of days it really turned for the worse. It is about 2/3 gone.

I have had success with a catââ"šÂ¬Ã¢"žÂ¢s-paw and two other Acropora. This is the first time I have had any problems with this tank. Parameters are close to perfect. 400 watt halide lighting.

When I looked closely, I found these two crabs on it. I need to know if these are good guys or bad guys?

 

[clkwrk]

1. no good

2. good

 

[JPSwanHome]

Thank you for your quick response!

Would the first one actually cause regression in the acro?

What kind are these?

 

[clkwrk]

Yes it would as it eats sps flesh and polyps.

The second guy is commonly found in pocci's and stylos but will live in any acro if the others aren't around.

I have a breeding pair of those.