LFS convinced me to add emerald crabs, buyer’s remorse?

[canjosh]

Went to the only reputable LFS within 120 miles today looking for some additions to my CUC. Tank is about 4 months old, have some hair algae, nothing too crazy. The LFS has always seemed reasonable with decent advice. They seem to take great care of livestock, etc. But they were gobsmacked that I don’t have emerald crabs and I kinda felt like a dummy so went ahead and bought 5 of them (135 gal DT).

Now I’m wondering if I should’ve just stuck with my gut. Everybody’s experiences seem to vary quite a bit with emeralds, but the LFS guy said he’d never had issues other than with huge males, etc

My major concerns are that my coral priorities are LPS/euphyllia and I’ve got small fish that burrow (a Yasha goby/pistol shrimp—both very small, and a court jester Goby).
Thoughts?

 

[JayM]

I added one to help control some hair algae while my tank was fallow. Saw him once or twice, but never near coral or hair algae, and then he disappeared.

I’ve since added my fish back to the tank and my Foxface has absolutely ravaged every last bit of hair algae. Highly recommend if you have a large enough tank for one.

 

[Tired]

I like a nice tuxedo urchin for hair algae control.

 

[canjosh]

I added one to help control some hair algae while my tank was fallow. Saw him once or twice, but never near coral or hair algae, and then he disappeared.

I’ve since added my fish back to the tank and my Foxface has absolutely ravaged every last bit of hair algae. Highly recommend if you have a large enough tank for one.

Yes, a Foxface is in the plan.

The emeralds all appear to be females on close inspection, so I guess that’s a good thing. I’m sitting here temp acclimating them, trying to decide whether they’re worth the risk.

 

[Sharkbait19]

Generally a crab isn’t a threat to any healthy fish, and most inverts will be left alone as well.
Emeralds are generally good for bubble algae, so nice having a few on hand for when that shows up.
Only one of mine has ever been a problem, it ate a serpent star and ripped some clove polyps off rocks, the rest have been more or less model citizens.
With ample food, I don’t see why you should have a problem.

 

[MrGisonni]

I have a male that started getting friendly with one of my Montipora. I grabbed him with my aquarium tongs but he escaped me. Apparently he learned his lesson. He has been a model citizen since.

 

[canjosh]

Well, as a follow up to this, all the crabs initially seemed to actively be munching on algae on the rockscape and picking through the sandbed.

However, tonight I just observed one of them actively ripping polyps off a hammer and eating them. So she’s out of the tank after 48 hours. I guess this is why some people say emeralds can’t be trusted. Hey, just like people I guess each has their own taste. I have a couple of small frags that could be devoured pretty quickly, so I’m glad that I happened to be walking by the tank while it was chowing down

 

[LeannaBanana]

Well, as a follow up to this, all the crabs initially seemed to actively be munching on algae on the rockscape and picking through the sandbed.

However, tonight I just observed one of them actively ripping polyps off a hammer and eating them. So she’s out of the tank after 48 hours. I guess this is why some people say emeralds can’t be trusted. Hey, just like people I guess each has their own taste. I have a couple of small frags that could be devoured pretty quickly, so I’m glad that I happened to be walking by the tank while it was chowing down

Oof that's bad luck. Glad you caught it, though! I had one emerald that developed a taste for LPS that put me off of them for a while. He got sumped. Since then I had a bubble algae problem and my emeralds have all been pretty good. I'm knocking on wood as i type because that's how these things go. Hopefully your others are fine!