Wicked Bad Emerald Crab

Griff · Jun 24, 2016

I purchased an emerald crab to eat some bubble algea I had in the tank. He did a great job. It was gone in a week. Granted I didn't have that much.

Ever since he has wrecked havoc in my tank. He ate half the polyps off my bird of paradise. He killed multiple snails including my orange chestnut. He knocks styuff over. I've caught him munching on my Duncan. He may be responsible for the death of a fire fish and or Midas blennie as well.

Anyone have a similar experience with these guys.

My new 525L will only have snails and the few hermits I already have in my existing 30g. I'm not buying crabs or hermits anymore! They are evil. It's a shame too because I love the diversity they bring to the tank.

chefjpaul · Jun 24, 2016

Crabs are food not friends

Zenlikeyoda · Jun 24, 2016

wow that is a bad crab! Is it very large? I have never had any trouble with my Emeralds but they were about an inch long shell tip to tip (They never grew very fast). Mine would come out in the evenings to walk over the sands from one corner of the tank to the other so maybe catching your to re-home will hopefully be painless and easy!

NanaReefer · Jun 24, 2016

Wish mine would eat BA grrrrrr.

RJinPV · Jun 25, 2016

My LFS sold me 8 emerald crabs to attack my hair algae. I have one emerald crab left and more of the hair algae than I had when I started. One by one the crabs disappeared. I actually witnessed my last crab flip a Trochus snail over and start dining in it. I am loosing ~5 snails a week and I suspect my crab is doing it.

smokin'reefer · Jun 25, 2016

I have 3 or 4 in my 90 gal without any problems. I did have 1 smaller one nipping at a lepto so I banished him to the sump.

Griff · Jun 25, 2016

My IM Nuvo is an all in one and has no sump

Salty1962 · Jun 25, 2016

They are crabs and they will eat whatever they can get the grimy claws on. I had one clear out all of my gobies.

Eaj1001 · Jun 25, 2016

I have 2 in a 25 both are good bubble algae eaters (not much left) but no issues so far.

Shaggy · Jun 27, 2016

I've never had good luck with them, like others they have always eaten my snails before the bubble algae.

CodyRVA · Jun 28, 2016

They're opportunistic hunters. My pair of emeralds did the same thing, loved zoas. My coral banded shrimp acted similarly, but never went after coral; did catch a fish and several snails/hermits though. When food is scarce, anything can end up on the menu.

Cruz' Reefing · Jun 28, 2016

I've had my emerald crab for 6 month and haven't had any issue yet and it did a pretty good job cleaning up the bubble algae.

certain_code · Jun 28, 2016

Mine ate all the little stuff but never touched the bubble algae. Figured, eh I will leave him to get any scraps and feed him from time to time with meaty goodness to make sure he doesn't die.

Well, my Duncan heads are almost all gone now after 1 night it deciding to go at it. Banished it to the sump to take care of that mess only to have it eat a fish that was previously banished awaiting a trip back to my LFS.

No more crabs for me to say the least.

shred5 · Jun 28, 2016

mine ate all my shrimp once..

elimav · Jun 29, 2016

I bought several to eat BA, they didn't help. However, they did eat my scarlet skunk shrimp and my fire shrimp!

James Emory · Jun 29, 2016

As one member said, crabs are opportunistic feeders. Emerald Crabs may very well eat Valonia if no other food source is present. I have had several Emeralds in the past 15 years and not one has ever eaten bubble algae.

CodyRVA · Jun 29, 2016

James Emory said:
As one member said, crabs are opportunistic feeders. Emerald Crabs may very well eat Valonia if no other food source is present. I have had several Emeralds in the past 15 years and not one has ever eaten bubble algae.

+1, mine ate all of my bubble and hair algae, but shortly there after went for the softies. Only good thing is crabs aren't overly intelligent and are typically quite easy to catch and remove.

Tristan · Jun 29, 2016

Mine ate my Utter Chaos Zoa. It also destroyed my caulerpa in the main. I thought they only ate bubble and hair

kptompk · Jun 30, 2016

I have one and he is great. I feed him little bits of cod fish every other day. He comes out of the rock and takes it right out of my hand. If I don't have his tidbits he will hook on to the rock with his back legs, and hold on to my finger with his front legs, and clean my finger. He also catches small bristle worms now and then. I feed him and my large hermit little bits of cod fish I got from the fish counter at the grocery store. My coral banded used to eat the cod fish but he just goes after bristle worms now, and what ever else he picks off the rock. I also feed seaweed strips I get from the grocery store. I have not seen my emerald eat them, but my hermits love them.