What do Emerald Crabs Actually Do?

[CCXGT]

Considering getting a small one for my 10G.

Read a lot of mixed opinions online about wether they're reef safe or not, wether they actually eat anything, wether they kill other invertebrates...

So can anyone recommend them through personal experience?


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[Sniperhank]

Crabs are opportunists. They will eat what they can. It will eat algae, but if there aren't any algae it can easily develop a taste for corals.

[likeaboss2645]

As long as you have algae in your tank it shouldn't eat coral


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[Sillyfishies]

The emerald crab do, what the emerald crab do.

This means eating things they shouldn't. I currently have one, but I watch it closely... very closely. Luckily it's a slow mover, and would be easy to take out. My sally lightfoot crab on the other hand, got a rock smashed on him. He was too fast for his own good. Not to mention he was big enough to eat fish, if he could catch one.

[Rockster2]

I've had from 4 to 6 of them in my 220g tank at all times over the last few years. I've only witnessed them eating algae in the tank with one exception. I had one that occasionally clipped off zoa heads. I will sometimes add a clip of seaweed at night (when the tangs are sleeping) to make sure they have enough to eat.


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[mr_X]

I like to watch them, but I've witnessed them eating soft corals. At one point I would order a dozen at a time because I liked to look at them, and they seem to hide a bit when the lights are on. this way the odds of seeing one were greater in my large tank. It seems that one out of a group would get large and would kill off the rest. I had a large one that liked to hang under a birdsnest colony, but never did anything detrimental to it. Here he was-

[CCXGT]

Is it worth the risk getting one for a 10G?

If not I'll probably just do a Snail only crew.


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[mr_X]

That's hard to say. It's up to whether you like them enough or not. Personally, I don't find snails very exciting.

[CCXGT]

Originally Posted by mr_X

That's hard to say. It's up to whether you like them enough or not. Personally, I don't find snails very exciting.

I'm not too sure any member of the CUC is all that exciting..


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[Vague]

I think some are pretty interesting my emerald just molted came out looking like the hulk... Now he isn't so shy... Got a fighting conch we nicknamed creeper 😀

[mr_X]

Originally Posted by CCXGT

I'm not too sure any member of the CUC is all that exciting..


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You don't even need a "clean up crew". If that's why you ware wanting snails and crabs, you can skip them entirely with no Ill effects.

[CCXGT]

Originally Posted by mr_X

You don't even need a "clean up crew". If that's why you ware wanting snails and crabs, you can skip them entirely with no Ill effects.

Yeah I know.

I mean the tank is a month old and I have no signs of any algae whatsoever...

Obviously I'd like to not have a CUC but I'm planning just in case.


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[mr_X]

If there is no algae, then you don't have enough food to keep some of these creatures anyway. Just feed reasonably and keep good husbandry/water changes and you'll be fine.

[CCXGT]

Originally Posted by mr_X

If there is no algae, then you don't have enough food to keep some of these creatures anyway. Just feed reasonably and keep good husbandry/water changes and you'll be fine.

Yeah there's no algae at the mo.. But you hear of many nano tanks that just get annihilated by a sudden algae bloom.

I'll definitely do my best to keep it nice and clean.


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[alyxandria]

They look cute and wave their claws at you lol. At least mine does haha. He eats algae as well, always seems to be eating.

[Gregcoyote]

I think they are pretty cool, but not a algae cure IMO. Never had a problem with them eating polyps, but they are among a few crabs that are even this trustworthy. I like a small CUC but it isn't a cure for much except to dislodge food particles and some algaes that hang up in the rock work, but they digest this and poop it out anyway, so your filter is removing the excess food and algae nutrients regardless. Your just running it thru a crab first. There is a old joke there somewhere...


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[Anovack]

Mine just hangs at the base of my cats paw coral and doesn't seem to be feasting just hanging


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