Emerald Crab?
Printed From: Utah Reefs
Category: Specialized Discussion
Forum Name: Invertebrates
Forum Description: This is the place to ask questions about invertebrates.
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=30022
Printed Date: August 04 2025 at 4:29am
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Topic: Emerald Crab?
Posted By: fishinmonkey
Subject: Emerald Crab?
Date Posted: December 11 2008 at 7:44pm
| New to the hobby and was wondering if anyone had a problem with emerald crabs killing hermit crabs? I have found 5 hermit crab carcases over the past week and no clue what is killing them. As I was watching my tank inhabitants tonight I noticed one of my emerald crabs jump on a hermit and was trying to get in its shell with its claws. If this is really happening does anybody want a emerald crab? |
Replies:
Posted By: Mike Savage
Date Posted: December 11 2008 at 7:57pm
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Hermit crabs, just like other crabs & shrimp, shed their old exoskeleton when they grow. Could this be what you are seeing? I've had great luck with Emerald Crabs and they are considered reef safe. Some people do report an occasional problem crab.
Mike -------------  |
Posted By: fishinmonkey
Date Posted: December 11 2008 at 8:12pm
| No it is definately not sheds, It is carcases. I saw 1 of my emerald's munchin on the guts of a hermit attached to the legs the other day and figured he was just scavaging. I was originally thinking my green spotted puffer was killing them until tonight that emerald was definately trying to kill a hermit. I have a peppermint shrimp that has disappeared. He use to come out and show himself and haven't seen him in 2 weeks. I wonder if he killed him also. Does anyone want a rogue emerald? |
Posted By: Mike Savage
Date Posted: December 11 2008 at 8:26pm
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If that is the case then I would get rid of that Emerald Crab!
Mike ------------- |
Posted By: Aquaristnewbie
Date Posted: December 12 2008 at 3:30am
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I will tak him if you really want to get rid of him ------------- 150 gallon Reef Millcreek Utah |
Posted By: BrandonA
Date Posted: December 12 2008 at 3:30am
| Don't know if it's just coincidence but i've had some hermits MIA also and I havn't seen my brittle star in about a week or so. Yesterday I looked all over for him and will look some more when i get home from work. I do have an emerald and I like the guy too. Better not be him. Also found my first Hermit crab in a snails shell yesterday. |
Posted By: fishinmonkey
Date Posted: December 12 2008 at 9:56am
| If you want to chance losing some cleaners. He is anyones to take. I have to wait till I can get him in a rock I can pull out and snag him, but YES you can have him. |
Posted By: tazman1982
Date Posted: December 12 2008 at 9:59am
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I have 2 in my 75 and all I see them eat is algae. and pinch at a bristle worm if it gets too close. but that is it. Are you sure it is an emerald? ------------- 75 Reef 55 Reef |
Posted By: DeepFriedOprah
Date Posted: December 12 2008 at 10:57am
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I have two emeralds in my 75, and they will eat any dead fish. They will fight with my pistol shrimp over a dead fish! ------------- "So, Just right in half? I have a very large one, Like 4" that I would like to frag, as well as a few smaller ones" Cameron |
Posted By: Mike Savage
Date Posted: December 12 2008 at 1:37pm
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You can try to trap him in a jar. Tip the jar against a rock and put some food in the bottom. Hopefully he will go into the jar to get the food and not be able to get a grip on the jar to climb out.
Mike ------------- |
Posted By: Mark Peterson
Date Posted: December 12 2008 at 5:03pm
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An Emerald crab that has turned to scavenging probably did so because there is not enough Macroalgae in the tank. They are not something a hobbyist should buy like we would buy a snail. They are specialized eaters of macroalgae, including small Valonia/bubble algae. Emerald/Mythax crabs have blunt/flat ends to their claws. If the claws do not have flat ends then it is not a true Mythrax. In that case we call them rock crabs because they come in as unwanted hitchhikers on LR. Rock Crabs need to be removed ASAP before they cause more trouble, like catching and eating a small fish. The method Mike mentioned is the best way to catch them. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member 
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