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"no crabs are reef safe" - really?!?!


ToXIc

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so my LSF has some Porcelain Crabs for $10. and i seen many posts stating the no crabs are reef safe... while doing some reading i'm finding the because they are primarily filter feeders the should bee reef safe..

 

anyone have any unsafe experience with them?

 

oh yeah... would they bother my sexy shrimp?

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I havent heard anything negative about these guys but have never had them. Was curious about them myself. Some crabs get a bad rep I believe and that's why most say dont have them. I say the same as well but do keep a couple scarlet hermits in my tank.

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I love to have a porcelain. So far, I have a well behaved emerald and hermits. Bought the emerald to eat the tiny patch of Gelidium I have. But, he doesnt touch it or it is too hard for him to pull. Anyway, gelidium patch is not growing at least thanks to Chaeto.

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Yes, well fed... I'd suggest target feeding if you are not already.

 

I love watching my big hermit crab snatch a peice of shrimp when I feed him. Just so you know he is in a large mex turbo shell. I am going to need to get a bigger tank just for him.

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I have had a couple of porcelain crabs.. they are filter feeders (primarily) and have never bothered any of my corals. IMO they are completely reef safe and fun to watch. They never bothered my shrimp but they would nip at a fish if they got to close.

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The thing is, no crab really is reef safe. Porcelain crabs included. Throw some frozen mysis in the tank. I promise you, that crab is going to grab a chunk of it to eat. Now imagine that mysis being a small, inactive fish. There is your answer.

 

Sure, for the most part, most of the crabs we keep are generally going to leave things alone. However, given a chance, they will take a meal where they can get it. Personally, I like me some crabs, so I keep em.

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Watching my porcelain crab go after mysis, I'd be shocked if he could grab even a small inactive fish. He's very slow and very clumsy with his claws. It takes him multiple tries to grab even stationary bits of food. I feel like I practically have to drop it right onto his face if I want him to eat larger chunks. (and by larger, I mean anything too big for him to catch by filter feeding)

 

So while I understand the words of caution, I think porcelain crabs are about as reef safe as you can get. I trust mine with my gobies and so far have seen no compelling reason not to.

 

If you're looking for other reef safe crabs I'd also put in a word for pom pom crabs. They also stay small and are relatively peaceful (though more cryptic) I've had mine for almost a year now and she's never shown any interest in my fish or other inverts. Then there are Trapezia - commensal pocillopora/acropora crabs - which I don't own, but have heard good things about, if you ave SPS colonies.

 

Of course, as always, this is all anecdotal, YMMV.

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burtbollinger

In direct observation...I know for a fact that sally lightfoot and emerald crabs are fish killers...

 

My porcelean seems as peaceful as can be though...but then i believe he isn't technically a crab.

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I have a Pom Pom Crab which is very well behaved.

I also have a crab that came in via hitchhiking on my live rock of turtle weed I think, I believe that he is an emerald crab. I have not known he had come along until about three weeks ago so he may cause animal harm in the future. He has not bothered my sexy shrimp which I introduced at the same time as my turtle weed, but he ate almost all of my turtle weed. I did not even know he was there until he finished off the macro algae and I saw him standing on the rock. I have only seen him a couple of times since then, mostly hanging on to the bottom side of a rock. I am still rather irked that he turned my $25.99 macro algae into $25.99 crab food.

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My acro crab just stays hidden in his nirdsnest colony and I seldom see it, except when I target feed him. And even then I only see his pincers reaching for the mysis.

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I would not worry about a porcelain crab. If you get one that stays out in the open they are fun to watch when they feed. Unfortunately I have never had one last more than 6 month. You could check out Pom Pom crabs also. They seem a bit more hardy and I have never had a problem with mine, which is almost 2 years old now.

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Porcelain crabs are not "true" (anomuran) crabs. They are more closely related to squat lobsters and hermit crabs (Brachyurans). Hermits, being omnivorous, behave very similarly to true crabs. Porcelains in general are very peaceful.

http://www.reefhobbyistmagazine.com/downlo...df/version9.pdf

 

Got that backwards--hermits, porcelain, and anemone "crabs" are Anomurans. True crabs are Brachyurans.

 

Semantics aside, what lak said. :D

 

The only brachyurans I can think of that are safe with corals, fish, and anything but tiny invertebrates are the commensal crabs that come in with Pocillopora/Acropora colonies.

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Depends upon what you mean by "reef safe." While many commonly available ornamental crustaceans are indeed safe with corals, they are not safe for meiofauna and macrofauna in and on rock/sand. If you are looking to maximize diversity of these animals (including various 'pods), then you may want to reconsider most larger ornamental crustaceans. I don't have any in my system for this very reason.

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Only problem I ever had with my porcelain was that it was so disruptive to my RBTA that it forced a split. After that, he got demoted to another tank.

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The thing is, no crab really is reef safe. Porcelain crabs included. Throw some frozen mysis in the tank. I promise you, that crab is going to grab a chunk of it to eat. Now imagine that mysis being a small, inactive fish. There is your answer.

 

Sure, for the most part, most of the crabs we keep are generally going to leave things alone. However, given a chance, they will take a meal where they can get it. Personally, I like me some crabs, so I keep em.

 

Definitely +1. I witnessed a hermit crab grabbing a newly introduced yasha goby at my lfs and started eating at it away alive, even though it was fighting to break free. Soon, more hermits came in for the easy meal. Luckily since I was there to witness it I informed a worker who immediately put all the hermits into another holding tank. The original attacker went back inside his shell, dragging the yasha's tail along with it into its home. Only after a few seconds did the hermit finally release the yasha, who now had a torn tail fin and some red marks on his tail. And before all of this, I was actually thinking about taking that yasha home. :(

 

On topic of the porcelain crab, my anemone porcelain crab has been a model citizen but I believe he's starting to annoy the rose that he hosts since the rose no longer fully expands like it used to prior to the addition of the crab. So I too think a split is in order for my porcelain anemone crab.

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porcelain and pom pom crabs are safe for the tank. *ALL* other crabs including hermits are not. But caveat empitor here because if they do not stay fed and are hungry to the point of starvation then *ANY* animal/fish/crustacean/etc will take action outside the norm to stay alive.

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My emerald is now coming into open during feeding time. It jumps and catches passing by mysis. Also snaps at passing by fish. Hope it is a defensive gesture. But I am getting worried.

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So far my hermits and emerald just crawl around grazing and leave the few corals I have along with my snails, dottyback and blenny alone. The emerald and blenny hang out in the same cave areas until feeding time, then everybody comes out to snatch a free meal. It's fun watching everyone take their meal back to a safe area to eat. :happydance:

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