Emerald Crabs are NOT Reef safe!

[Diznaster]

I know plenty of you have them with no problems. I wasn't so lucky. I had one that loved to eat my SPS. I saw it going to town on a staghorn SPS frag the other night. I made a trap to try and catch it. Jar with small opening, baited with Mysis in a mesh pouch. The emerald could care less, walked right past it to munch on coral. The hermits loved getting into the trap though. While I was trying to catch the emerald crab I knocked the frag it liked to eat off the rock. I moved the frag to the other side of the tank and left the trap in place. Next day the crab moved to the other side and kept eating the frag. I moved the frag again and moved the trap closer to the crab. He passed by the trap and started eating my Oregon Tort instead. I went ninja mode and snuck up on it and stabbed it with a small screwdriver. Glad I got rid of it and I will never put one in a tank again. I don't enjoy watching corals get eaten or stabbing creatures that eat them.

 

[Diznaster]

I meant reef not feef, lol (cant change the title)

 

[maroun.c]

I meant reef not feef, lol (cant change the title)

Looks like Reef to me

 

[Diznaster]

Looks like Reef to me

Thanks for the fix Mr. Wizard!

 

[maroun.c]

Most welcome. Well they are still crabs which by definition are opportunistic feeders. They have been known to munch on corals in some tanks. I added two to deal with some bubble algae m9bths back and they never touched anything and cleaned up there alga very fast.

 

[alton]

There is always a chance that a fish or invert is not going to be reef safe. I sold a Purple Tang out of a softie tank many years ago and the person added it to a a SPS tank. In the next two weeks it destroyed hundreds of dollars of SPS before they could remove it.

 

[norfolkgarden]

I know plenty of you have them with no problems. I wasn't so lucky. I had one that loved to eat my SPS. I saw it going to town on a staghorn SPS frag the other night. I made a trap to try and catch it. Jar with small opening, baited with Mysis in a mesh pouch. The emerald could care less, walked right past it to munch on coral. The hermits loved getting into the trap though. While I was trying to catch the emerald crab I knocked the frag it liked to eat off the rock. I moved the frag to the other side of the tank and left the trap in place. Next day the crab moved to the other side and kept eating the frag. I moved the frag again and moved the trap closer to the crab. He passed by the trap and started eating my Oregon Tort instead. I went ninja mode and snuck up on it and stabbed it with a small screwdriver. Glad I got rid of it and I will never put one in a tank again. I don't enjoy watching corals get eaten or stabbing creatures that eat them.

Um, not that you want the coral damaged even more, but in the future, what about putting the favorite coral in the trap instead?
[emoji4]

 

[ReefdUp]

Nope... good luck trying to get everyone to accept that wild creatures are just that... wild. Crabs are opportunistic, and I've had them go rogue every time once they got anything above a tiny size.

I've seen tangs eat corals. Everyone seems to gloss over that clown gobies destroy SPS and small shrimp. The list continues.

 

[Diznaster]

Um, not that you want the coral damaged even more, but in the future, what about putting the favorite coral in the trap instead?

That's a good idea and had I thought about that. I wasn't sure if I could find a home for a the rouge crab. Then it decided to expand its palette and experience new flavors. I saw the T6 torx driver on my desk and went rouge myself. Trust me it won't happen in the future, I won't risk getting another one.

 

[vetteguy53081]

These lost my trust a long time ago. Had a tank with bubble algae and bought 2. Chromis killed one and the other I caught more than once scraping away on monti and picking at Zoas.
Rediculous!

 

[Mattrg02]

I had one of these devils. I didn’t kill him though. Ending life that I put in place just feels wrong. I managed to catch him bare handed while he ate on my $50 yellow fin fairy wrasse that he caught. I promptly put him in the sump where he lived out his days. He was also a coral muncher.

 

[Murica]

I have two for a 240 gallon tank. I always wayyyy under the suggested amounts whenever I get something iffy/potentially hazardous. I think that since there's so much food for only two crabs, mine have never touched coral or fish

 

[SPEEDBUMP1204]

I caught mine eating my gsp and convicted him. He was evicted that night. I put what was left of the gsp in a mason jar and propped it up against the rocks. Had him caught in less than 30 min.

 

[iDeath]

I don't put any crabs or shrimp in any of my tanks. They are all potential problems in my experience.

 

[theKoolAidMan]

I agree mithrax crabs (both emerald and red) can be hit or miss. I had two in my tank. One was small and one was very large. Like silver dollar large. The big one was an SOB that would grab my nassarius snails by the shell and try and drag them away. He also took a fist sized frag of GSP and tried to carry it off to his lair. He was returned to the LFS. The small one is still in the tank and doesn't seem to cause any problems.

 

[Mattrg02]

I should mention that he didn’t touch the bubble algea that he was brought for.

 

[JeannieS]

I happened to be watching one day when I saw my emerald crab reach up and grab one of my duncan's tentacles. He strung the tissue out like a piece of spaghetti, put the end in his mouth and started munching back toward the duncan. He was promptly re-homed and has not been replaced.

 

[Reefpuck]

Just added a small one yesterday...so we will see. Got plenty of algae for it to much on.

Is there a chance they go after corals/fish/inverts when the algae supply is slim?

 

[Ferrell]

I’ve had one for several months and he decimated the bubble algae and now I just feed him reef frenzy to keep him full. Just added another small one yesterday.

 

[Diznaster]

Ending life that I put in place just feels wrong

I totally agree, I wanted to catch it and put it on sump duty or give it to LFS. Then again making it live in a dark prison or passing on the pain doesn't make me happy either. I'm sad that I killed it, I won't get another one because I don't want to do that again.

I put what was left of the gsp in a mason jar and propped it up against the rocks.

I do a lot of food canning so I have plenty of mason jars and lids. It is a great idea, heavy and sinks. I used a small one, cut a hole in a lid and baited it with shrimp for days. If I would have baited it with coral the emerald crab would have probably been caught sooner.