I thought they were safe with fish, but last night my emerald crab attacked a blue tang i just bought. I just put him in yesterday afternoon and seemed fine. i checked later and the tang was in the rocks and looked like he was stuck. i picked the rock up and my emerald crab had him by the cohones. i flicked the crab in the head and he released the tang. Im worried about these emeralds now. should i pull them out?
Emerald Crab attacks!
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Hmm....I would first rule out that the Tang wasn't sick to the point of being close to death....and the crab was doing you a favour by starting to eat it. It's very common for a NEW blue Tang to be fine at night and dead by morning....Not that crabs don't eat fish....it's just that most fish are too fast or too big for an emerald crab.
amazingbobby
New member
crabs... you just can't trust the shady suckers
crabs... you just can't trust the shady suckers
I had an emerald crab. He would cower in the nearest crevice if a fish came near. Unless your tang was small and stupid or as mikeshook said, "near death," I am suprised by the attack.
crabs... you just can't trust the shady suckers
I had an emerald crab. He would cower in the nearest crevice if a fish came near. Unless your tang was small and stupid or as mikeshook said, "near death," I am suprised by the attack.
RichConley
New member
Yeah, your tang is on its way out. Tangs dieing overnight because of low oxygen is pretty common.
benray4fun
New member
My emerald ate my skunk cleaner shrimp, so I'm not surprised in the least and the shrimp was pretty big!...
The Saltwater Kid
New member
emeralds are EVIL pure and simple. I would try to get him out if you can...unless you actually have one that pays attention to any bubble algae you have. I HAD one until one night I caught him trying to trim the tentacles of my Sun Polyps...back to the LFS he went!!!
RichConley
New member
If theyre trying to eat your corals, you aren't feeding your tank anywhere near enough. Buy a bigger skimmer, and feed heavier.
I have NEVER had a single problem with crabs/hermits/etc. Why? Because I skim heavy and feed heavy. Stop trying to starve your reef. These are supposed to be food rich environments.
The Saltwater Kid
New member
Well Rich the rest of the crabs weren't attacking/eating anything else they aren't supposed to and when i posted about my emerald there were others who had experienced the same problems so I guess I'm not alone.
Just feed enough to your tank in general. I feed a chunk of mysis and algae infused brine or Prime reef every other day. I skim heavily and everyone is happy healthy and fat...
Very few crab on crab hits... I have about 20 emeralds and about 50 hermits of all different varieties... I love the little guys. It would not be a reef tank without them IMHO. Along with about 100+ snails (trochus, cerith, astrea)... not much snail death either. I have so many snails (my trochus constantly are reproducing) that I don't notice one or two go missing every once in awhile when a hermit might need a new shell. It is all part of the ecosystem as far as I am concerned.
Very few crab on crab hits... I have about 20 emeralds and about 50 hermits of all different varieties... I love the little guys. It would not be a reef tank without them IMHO. Along with about 100+ snails (trochus, cerith, astrea)... not much snail death either. I have so many snails (my trochus constantly are reproducing) that I don't notice one or two go missing every once in awhile when a hermit might need a new shell. It is all part of the ecosystem as far as I am concerned.
jimwat
Premium Member
I've always had emeralds and have never seen one attack a healthy fish (or shrimp). I have one that is pretty big and ornery that will take an aggressive posture sometimes when fish swim near, but I've never seen it snap at anything. It will, however, pull a silverside right out of the mouth of my BTA if I do not chase it off first.
RichConley
New member
Exactly. If your hermits are killing each other, snails, etc, and your crabs are attacking things, you're not putting enough food in your tank.
I read an article a while back stating that 14kg of particulate food flows through a cubic meter of reef every day. Thats a TON of food, and thats what these animals are used to. Hermits/Crabs are smart enough to find other means of feeding themselves if you dont feed them.
Feeding very heavy and skimming very heavy is much better than trying to limit algae by underfeeding. Well fed animals are less aggressive, and less territorial.
The fact that other people have had the same problem with emeralds as you doesnt mean they aren't all doing something to cuase it (IE underfeeding)
I read an article a while back stating that 14kg of particulate food flows through a cubic meter of reef every day. Thats a TON of food, and thats what these animals are used to. Hermits/Crabs are smart enough to find other means of feeding themselves if you dont feed them.
Feeding very heavy and skimming very heavy is much better than trying to limit algae by underfeeding. Well fed animals are less aggressive, and less territorial.
The fact that other people have had the same problem with emeralds as you doesnt mean they aren't all doing something to cuase it (IE underfeeding)
The Saltwater Kid
New member
I believe I will try the piece of nouri wrapped around a rock (or some other way to get it near the bottom of the tank) as it sounds like a good idea that would benefit most everything in the tank.
rustybucket145
New member
Right on Rich, I'll add to that, I feed my emeralds, tangs, hermits and snails a variety of algae, not just the nori. You can go to an asian market and get bags of different types of seaweed. Just make sure it's not flavored. I think giving them a varied diet keeps them happy and eating what they are supposed to in the tank and not each other.
I also agree on the tang probably not being 100% healthy. Could be from the stress of the move, could be acclimation....etc. who knows? But I was just thinking.... if my largest emerald just so happened to grab onto my yellow tang, the crab would be going a one hell of ride.
And I guarantee that he wouldn't be holding on for long! A healthy tang should have absolutely no problem getting away from an emerald. Heck, they don't even have the proper claws to grab onto a fish.
On the crab trying to get at the sun coral.... are you sure he wasn't trying to get some food that the coral had caught? Quite often I have to fend off over-zealous hermit crabs that want some of the mysis that my sun caught. No biggie, just flick them off with the baster or tongs and give the coral time to gobble it down.
I also agree on the tang probably not being 100% healthy. Could be from the stress of the move, could be acclimation....etc. who knows? But I was just thinking.... if my largest emerald just so happened to grab onto my yellow tang, the crab would be going a one hell of ride.
And I guarantee that he wouldn't be holding on for long! A healthy tang should have absolutely no problem getting away from an emerald. Heck, they don't even have the proper claws to grab onto a fish.On the crab trying to get at the sun coral.... are you sure he wasn't trying to get some food that the coral had caught? Quite often I have to fend off over-zealous hermit crabs that want some of the mysis that my sun caught. No biggie, just flick them off with the baster or tongs and give the coral time to gobble it down.
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