SPS PE and Emerald crabs

[sfg]

I'm pretty sure I know the answer to this but I hoping someone can speak from experience. I have about 30 small emeralds in my 120G, i know i know.. that's a lot. I had 50 at one point but re-homed all the big ones after they cleaned up an algae mess I had awhile back. Anyway, they are EXCELLENT at keeping the house in order, BUT.. i'm not seeing the PE that I am expecting.

In fact, at night time when PE is always at it's best, it's non existent in my tank. I'm sure this is related to the fact that the emeralds all come out at night to scavenge.

Can anyone speak from experience that these crabs indeed do affect PE on SPS? It's an SPS dominant tank so im not too worried about them picking at LPS.

Thanks

 

[Angelwolf21203]

Following. This may be why I have the same problem.

 

[Rick5]

I'm pretty sure I know the answer to this but I hoping someone can speak from experience. I have about 30 small emeralds in my 120G, i know i know.. that's a lot. I had 50 at one point but re-homed all the big ones after they cleaned up an algae mess I had awhile back. Anyway, they are EXCELLENT at keeping the house in order, BUT.. i'm not seeing the PE that I am expecting.

In fact, at night time when PE is always at it's best, it's non existent in my tank. I'm sure this is related to the fact that the emeralds all come out at night to scavenge.

Can anyone speak from experience that these crabs indeed do affect PE on SPS? It's an SPS dominant tank so im not too worried about them picking at LPS.

Thanks

I'm a fan of including emerald crab in my clean up crew and I'm typically heavy-handed in terms of the number that I keep, but with 30 you may be asking for problems, even in a 120 gallon because I would think you may have a difficult time keeping them fed, encouraging the rogue crab or two to nip at your coral. Having that said, if you aren't noticing physical abrasions on the coral, the crab could just be disrupting polyp extension by touching the coral, even if the crab aren't nipping (and with 30, you kind of increase the chances that a crab is brushing up against a coral at any given time, causing the polyps to retract). Having that said, are all of the coral showing a lack of polyp extension and if so, have you looked elsewhere, just in case?

If the outbreak is over (e.g. bubble algae), I'd keep no more than a dozen.

 

[sfg]

I'm a fan of including emerald crab in my clean up crew and I'm typically heavy-handed in terms of the number that I keep, but with 30 you may be asking for problems, even in a 120 gallon because I would think you may have a difficult time keeping them fed, encouraging the rogue crab or two to nip at your coral. Having that said, if you aren't noticing physical abrasions on the coral, the crab could just be disrupting polyp extension by touching the coral, even if the crab aren't nipping (and with 30, you kind of increase the chances that a crab is brushing up against a coral at any given time, causing the polyps to retract). Having that said, are all of the coral showing a lack of polyp extension and if so, have you looked elsewhere, just in case?

If the outbreak is over (e.g. bubble algae), I'd keep no more than a dozen.

i have "ok" PE during the day, but none at night. When I break out the red flashlight its crab city in the display. I don't suspect pests, just wondering if the dense population would attribute to lack of "better" PE.

I guess i'll start rounding them up and keep them in the sump and see how things change in the display.

Appreciate your time