EMERALD CRAB BEWARE

[Blue Topia]

Just want to share my experience. Emerald crabs are absolutely positively not even close to being reef safe. Fish only ok but not in reef tank. 

 

I've tried many and my last one would eat a Scoly at night and I woke to it being shredded by him. He also are half my green star polyps and ate a rare SPS. He was fed a lot and had algae to graze on but they are coral eaters all the way.

 

I will never get another unless fish only. Most people are not even aware they are eating their corals. 

[Matteo]

Mine would pull food out of my btas mouth. I threw him in my predator tank when I had it... 

[Lalakuno]

I've had nothing but great experiences with emerald crabs. I have 10 in my 40gal. They play king of the hill on one of my rocks all day. 🤣

[Seadragon]

I think the only crab I'd ever want is a Pom Pom Crab.  Damn things look so cute!

[Tamberav]

1 hour ago, Seadragon said:

I think the only crab I'd ever want is a Pom Pom Crab.  Damn things look so cute!

Most pom pom crabs are great! I did get one evil one though that attacked fish and other inverts. I think @Clown79 had one evil one once too? 

 

Previous ones I had were shy though. 

[mcarroll]

Never turn your back on a hungry crab.  

 

(Motto of all ocean life, I bet.)

 

 

[Clown79]

6 hours ago, Tamberav said:

Most pom pom crabs are great! I did get one evil one though that attacked fish and other inverts. I think @Clown79 had one evil one once too? 

 

Previous ones I had were shy though. 

Ya I did. It even killed another pom pom.

[Tired]

Emeralds are very hit-or-miss, and I suspect some of the 'miss' ones are just ones that learned there's food somewhere the 'hit' ones don't know about. Food inside coral, food IS coral, that sort of thing.

[Seadragon]

On 11/23/2019 at 4:13 AM, Tamberav said:

Most pom pom crabs are great! I did get one evil one though that attacked fish and other inverts. I think @Clown79 had one evil one once too? 

 

Previous ones I had were shy though. 

 

On 11/23/2019 at 10:57 AM, Clown79 said:

Ya I did. It even killed another pom pom.

 

Thanks for the insight!  I think you both, along with some research I've done, convinced me to look elsewhere for a more peaceful crab.  At first, I didn't think such a thing might exist, but I somehow came across something that I bet fits my criteria of the most peaceful crab of them all.

 

What does everyone think about Porcelain crabs?  I can't find anything negative about them, and they kind of remind me of my Bamboo shrimp in my freshwater aquarium!  Filter feeders FTW!

 

[NanoTrav]

I got an emerald crab to help with hair algae. Didn't help at all, and would take the food out of the corals mouths. Glad he died. He disappeared awhile ago, I'm certain he died.

[Tamberav]

26 minutes ago, Seadragon said:

 

 

Thanks for the insight!  I think you both, along with some research I've done, convinced me to look elsewhere for a more peaceful crab.  At first, I didn't think such a thing might exist, but I somehow came across something that I bet fits my criteria of the most peaceful crab of them all.

 

What does everyone think about Porcelain crabs?  I can't find anything negative about them, and they kind of remind me of my Bamboo shrimp in my freshwater aquarium!  Filter feeders FTW!

 

Every porcelain I have had has been peaceful.. They are not true crabs... They are related to the squat lobster. 

 

The anenome ones will be out in plain sight. The other kinds are a bit shy. 

[sadie]

3 hours ago, Tamberav said:

Every porcelain I have had has been peaceful.. They are not true crabs... They are related to the squat lobster. 

 

The anenome ones will be out in plain sight. The other kinds are a bit shy. 

😅 squat lobster...I have never heard of that, I laughed out loud.  I had to look them up, some of them are freaky looking, the hairy one's are cool looking.

[Clown79]

42 minutes ago, sadie said:

😅 squat lobster...I have never heard of that, I laughed out loud.  I had to look them up, some of them are freaky looking, the hairy one's are cool looking.

I like this one, love all the spiky hair. Lol.

[mcarroll]

If you have a nice large coral head, they seem to like to hang out on/in them.  I suppose it's anemone-like.  😉  

 

I've got two Porcelain's in my 125 Gallon and I see them almost every day.  Usually on my volleyball-sized birdsnest.   There is some incidental damage on the birdsnest that I think is from them. (There were issues related to the move into this tank too, but I think I've ruled them out at this point.)  I think it's only from them walking around on the coral while they're plankton-collecting...and the damage is mostly confined to their favorite spot for catching plankton, so they're in that spot repeatedly.  Wouldn't be very good for a frag, but it's very incidental on a colony this size.  Haven't seen them on a frag before....which prolly wouldn't seem the same to them, so don't think I'd even worry.

 

They're literally built like a lobster, BTW.....tail and all.  (Apparently more closely related to the hermit crabs.)  <---Good link!  But brief.

 

Their tail is normally folded up under the carapace though, so as to complete their crab "disguise".  (Aka "Carcinisation")

 

The porcelain crab's tail looks just like this lobster's tail when it's out:

(Couldn't find a single pic of a porcelain crab with it's tail extended!)

 

Interestingly (at least to me), I had what was either a freshwater lobster or shrimp (maybe Bamboo Shrimp?) in a freshwater planted tank back in the 90's that had similar "fan shaped" plankton-collecting "hands" on its front legs as the Porcelain crab has...so that feature (along with crab mimicry) is shared elsewhere in the Decapod order too.

[SeaFurn]

5 hours ago, Seadragon said:

 

 

Thanks for the insight!  I think you both, along with some research I've done, convinced me to look elsewhere for a more peaceful crab.  At first, I didn't think such a thing might exist, but I somehow came across something that I bet fits my criteria of the most peaceful crab of them all.

 

What does everyone think about Porcelain crabs?  I can't find anything negative about them, and they kind of remind me of my Bamboo shrimp in my freshwater aquarium!  Filter feeders FTW!

 

Love my porcelain crab. Hangs out in my rock flower nems all the time and you gotta love their “mitts” they use to catch goodies out of the water column.

 

I put my emerald crab in my pico for a short time to take care of some algae. It also took care of a beautiful psammacora. It’s fine in in the tank with all the rock flower nems and some LPS. 

[Seadragon]

5 hours ago, mcarroll said:

I had what was either a freshwater lobster or shrimp (maybe Bamboo Shrimp?) in a freshwater planted tank back in the 90's that had similar "fan shaped" plankton-collecting "hands" on its front legs as the Porcelain crab has...so that feature (along with crab mimicry) is shared elsewhere in the Decapod order too.

 

I used to have a Vampire Shrimp aka Viper Shrimp (Atya Gabonensis) in my freshwater tank.  It looked just like a lobster too, but with fans. 🙂 I'm betting that's what you had before.

 

[mcarroll]

Wow....mine did have cool colors too but nothing like that!  Mostly reds and greens from memory.

[Tired]

Bamboo shrimp are the more common filter-feeders. Brownish, 2-3" or so. Viper shrimp are more unusual in the hobby and much larger, and are a different species. 

[Seadragon]

2 hours ago, Tired said:

Bamboo shrimp are the more common filter-feeders. Brownish, 2-3" or so. Viper shrimp are more unusual in the hobby and much larger, and are a different species. 

 

I prefer the Bamboo shrimp -- I still have 2 in my freshwater aquarium today.  They're always active and out front & center fanning the fastest current they can find for any food particles in the water.  The Vampire shrimp was hidden most of the time and I believe is nocturnal.  Difficult to feed regularly due to this and can die easily from starvation.  The Bamboo shrimp are easy to take care of like my Dream Blue Velvet Shrimp whom graze 24/7.

 

Speaking of ease of care, I hear the Porcelain Crabs are omnivores and will also eat the same food you feed to the fish if they cannot filter enough food out of the water.  I'm assuming the Porcelain Anemone Crabs are the same way, but I hear hide a lot less than the Porcelain Crabs.

 

I put an order in today for a Porcelain Anemone Crab from a nearby LFS.  (Should I get 1 or 2?)  The only thing that bothers me is they like to jack up their prices up around 2x - 3x what other online stores and farther away LFS charge.

[Proxo]

I've had great success with my emerald crab, cleared up my hair and bubble algae no problem.
Every now and again i'll hold some pellet food on tweezers next to him until he grabs it to stop him getting hungry enough to munch my coral!

 

[Tired]

Porcelain crabs are definitely peaceful. They're scavengers and filter-feeders, those big claws are just for show and shielding, 

"Porcelain crab" refers to several animals. The first is a sort of pinkish-white with spots, hosts anemones, and is sometimes called a porcelain anemone crab. The second is blue or brown with spots. The third is dark green-to-black and is often found in groups. All will tolerate each others' presence, all are peaceful and easy to feed, and all get around the same size. 

[Lovemyreef2015]

I agree, emerald crabs like all crabs are Opportunistic feeders. I would never trust a crab in my tank. Not worth it to me. Sorry you had to find out the hard way

[Frag Factory]

They are a risk, especially when hungry but I still love mine despite me being almost positive he ate some utter chaos...

 

I like to feed mine formula 1 pellets when algae is low, I just stick one on a BBQ skewer and wait for him to attack.

 

It works for me, I had one and it died. Over the next month bubble algae I never had popped up... I grabbed another and it's gone again.

 

Everything in reefing is a risk, it's part of the fun. The same stories can be told about peppermint shrimp which are the #1 aip killers and also fish that eat green stuff like fox faces. Many of these nibble at corals too.