Are Emerald Crabs Reef Safe

[Duncan Tse]

Bought a few rainbow acans a few months ago and it's all been doing well and plump. Just noticed 2 of them seem to be shrunken and not doing so well.

Then later today I've noticed my emerald crab is picking on my goni causing it to be shrunken and I suspect my crab may also be picking on my acan. I reduced feeding recently feeding only half cube frozen daily so it might be starving.

Do you suspect my emerald crab may be the culprit?

All my other acros montis chalices favias are doing great

 

[reefez]

I’ve got about 10 in my tank mixed reef I believe it’s a with caution thing but I’ve never noticed anything bad messing with corals or anything else they like algae and I feed pretty heavy so always stuff for them to scavenge look at live aquaria are Emerald crabs reef safe they say highly compatible in reef tanks scavenge for meaty foods and will feast on nuisance allergies

 

[Reefer37]

Personally, I've had no issues with mine, but I've heard and read of other people having this problem.

I thought I read something on another thread awhile back that the bigger ones (usually males) are more prone to it. Not sure how true that is, but I went with a smaller one (as I only have a 45g) and had him for a few months now, no issues.

 

[DMG Reef]

I have 4 emeralds in my mixed reef. They don't bother my acans at all. It's common for acans to inflate and deflate. I used to worry when I first got them but years later, I don't even notice now when they choose to deflate. As long as your parameters are within range, they're probably fine.

 

[Reefer37]

I’ve got about 10 in my tank mixed reef I believe it’s a with caution thing but I’ve never noticed anything bad messing with corals or anything else they like algae and I feed pretty heavy so always stuff for them to scavenge look at live aquaria are Emerald crabs reef safe they say highly compatible in reef tanks scavenge for meaty foods and will feast on nuisance allergies

Also agree with this!
I try to make sure my CUC doesn't rely on just algae for food, gotta make sure they eat too!

I try to throw pellets in there when I feed, specifically for the CUC. They all come running down the rockscape for bites. I've never seen an emerald crab move so fast.

 

[Duncan Tse]

Hm okay maybe I will give it a couple days and see how it does. I have noticed one time that a torch tentacle was floating around the tank but I'm not sure what caused that either. That was a couple months back and my torch now is looking healthy and splitting.

 

[reefez]

If your tank is very free of algae I try increasing you’re feeding like said
You did mention you recently decreased Feeding not sure if you noticed your problems after that or before

 

[Rrwilson1223]

Mine live in the refugium. Graze on the macro algae and sift through the detritus. Originally lived in the display but I was a little worried when one was constantly hanging around a nice colony of zoas.

 

[vetteguy53081]

I trust them as much as I do a politician
They Will turn on a coral in no time

 

[HellaDudes]

I've got a big fat male in a nano and as long as I feed enough sinking pellets for him to get his share, I've got no problems.

 

[Copingwithpods]

I have a small one that I have personally witnessed pick on recordia, zoas, Duncan's and candy canes. Takes a nip off the corals and then goes on his merry way. Never enough to kill any of them but definitely snaking on them. I'd say they are reef compatible WITH CAUTION. Not all emeralds will do that but 100% of them are capable of it.

2 weeks ago I witnessed mine pull a bulb off my recordia mushroom and eat it, it wasn't enough to kill it or even cause it to close enough for me to notice but it definitely did it which makes we wonder how often it's actually happening in other people's tanks and they just aren't noticing.

 

[Lukielight]

My RBTA before and after my emerald crab ripped the tentacles off of it.... I caught him red handed and he got evicted real quick.

 

[Auquanut]

I've always kept emerald crabs and never had a problem. I've got one that has grown massive. Named him The Kraken. That being said, there are loads of documented cases of emeralds eating/harassing corals. If he's a known offender, I'd sump him if you can catch the little terrorist. If you're happy with your feeding regime, there's no need to alter your routine to pacify a rouge emerald crab in my opinion.

 

[BighohoReef]

We’ve had three emeralds in our nano 30g everytime we’d add a new frag thecrabs would swarm it and pick off all the algae. We had a similar concern as the crabs would pick at our potted Goni. After a year we’ve had two crabs die and the Goni is thriving in full bloom everyday. We’ve had good luck with our emeralds just make sure you have a tank big enough to support them.

 

[Duncan Tse]

If your tank is very free of algae I try increasing you’re feeding like said
You did mention you recently decreased Feeding not sure if you noticed your problems after that or before

I've noticed it after I reduced feeding which leads me to thinking that it may be starving

We’ve had three emeralds in our nano 30g everytime we’d add a new frag thecrabs would swarm it and pick off all the algae. We had a similar concern as the crabs would pick at our potted Goni. After a year we’ve had two crabs die and the Goni is thriving in full bloom everyday. We’ve had good luck with our emeralds just make sure you have a tank big enough to support them.

So your goni started thriving after you removed the crabs?

Seems like it's a hit or miss after reading everyone's experience. Next time I see it I'll try to catch it with a pair of long tweezers. The crab's been with me for about half a year now and it's gotten so big.

 

[Copingwithpods]

I've noticed it after I reduced feeding which leads me to thinking that it may be starving



So your goni started thriving after you removed the crabs?

Seems like it's a hit or miss after reading everyone's experience. Next time I see it I'll try to catch it with a pair of long tweezers. The crab's been with me for about half a year now and it's gotten so big.

As you've noticed already from the responses emerald crabs are a 50/50 on their reef friendlyness. And if anything that is going into a reef has a 50/50 chance of eating coral well then it isn't really reef safe. I'd remove the crab and keep him out. Rehome it

 

[Parent_usmc]

My emerald ate my pepermint shrimp!