Porcelain crab really reef safe?

[Canneddynomite]

Took like 5 of these from my dads tank and he has like 50 of them. They all came in on live rock these people took from the coast I guess. I always thought they were harmless because people say porcelains are filter feeders only but the ones in my dads tank are getting Huge and all his tiny gobies and dotty backs are gone... Could they form a taste for live fish


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[d2mini]

I've noticed that any crab that gets big enough could just become an opportunistic feeder. They get to a certain size and our tanks just don't have enough food floating through the water column for filter feeders. Like emerald crabs for instance. Good when small, but questionable once they get huge.

 

[Bent]

I'm going to disagree with D2 here, respectfully. Porcelain crabs are not true crabs and are entirely reef safe. From what I've read their claws are just for show during mating and do not have any muscle ability to hold on to anything. I need to cite a source here, but I dunno if I'll be able to find where I read that.

But, I can say that I have upwards of 11 of those exact crabs. Some tiny and some huge, but I've never seen them do anything but wave their nets around.

They do need fed though FYI if you want them to thrive. I feed mine zoo plankton and puréed fish market slop with a turkey baster.

 

[d2mini]

I'm going to disagree with D2 here, respectfully. Porcelain crabs are not true crabs and are entirely reef safe. From what I've read their claws are just for show during mating and do not have any muscle ability to hold on to anything. I need to cite a source here, but I dunno if I'll be able to find where I read that.

But, I can say that I have upwards of 11 of those exact crabs. Some tiny and some huge, but I've never seen them do anything but wave their nets around.

They do need fed though FYI if you want them to thrive. I feed mine zoo plankton and puréed fish market slop with a turkey baster.

Yeah, I actually agree with you. I have never seen porcelains become a problem. I was generalizing. I just hate to say "never" with anything that is alive and has a mind of its own. haha

 

[ThRoewer]

Porcelain crabs are totally reef safe. I don't think they even have the extremities to actually feed of corals. Their big pinchers are primarily for self defense and not well suited for hunting. If you lock at them closely, from their shape and angle towards the body they actually resemble shields to fend attackers off. That said, if in a pinch, they are certainly able to harm a fish that harasses them.

I have 3 of the blue (or rather purple striped) ones from the Caribbean and 4 of the Indo-Pacific anemone crabs.
Saturday I will get 6 more (3 more Anemone crabs, 2 blue spotted and another purple striped)

The anemone crabs are the only ones that did fight with some of my fish: they caused a bit fin damage to my clownfish when I put them all together, but after the initial conflict everything has settled down and is peaceful now.

I think in general these crabs are way under represented in reef tanks.

 

[jgraz]

And porcelains will stay pretty darn small. Not sure what you mean by huge though. My first guess is they are not porcelain crabs

 

[davocean]

I was wondering if you actually had porcelain crabs too, can't really tell from that vid.
I've kept many, never have been, nor have I ever heard of them being an issue in any way.
Even my meanest and most territorial maroons permitted them in their nems, I don't think they would have permitted anything else even near, except maybe an anemone shrimp

 

[Bent]

Yeah, I actually agree with you. I have never seen porcelains become a problem. I was generalizing. I just hate to say "never" with anything that is alive and has a mind of its own. haha

Very true sir.

Fwiw by huge I mean like 1"

 

[kevantheman35]

Ive had one of good size in my reef for about 6 months or so now. He lives in my large bubble tip anemone and hasn't bothered a thing. He will occasionally eat mysis right out of my turkey baster tip which is cool.

 

[kevantheman35]