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Emerald Crab... sigh...

Discussion in 'Inverts and other Marine Animals' started by JodiI, Jun 18, 2018.

  1. JodiI

    JodiI Amphipod

    Have a beautiful purple/green digi that has been growing really well for about 2 years. Spread all over the rock, easily doubled in size, gorgeous coral.

    Until about three weeks ago, when I noticed a piece of it starting to die off. It was near a hole where an emerald crab hangs out, but was also overshadowed by a pink plating monti. So I fragged out the monti to give it some more sun.

    Didn't improve. Still dying off, and spreading. Not sure what was happening, I checked parameters. All good. Did a water change anyway. Coral still dying, and me very sad and confused.

    Until this evening, when I saw that $*(()#@ crab eating the coral. Like, pulling pieces off the live parts of the coral and eating it.

    Following 30 minutes trying to catch the crab (where he simply laughed at me from inside his cave while I splashed water all over the place and got attacked by the clownfish during my futile attempt), I broke off as many living pieces of the coral as possible and moved them elsewhere in the tank.

    Anybody else have this issue? Google says its not uncommon, but I simply hadn't heard of this before! Ouch! I'm going to make an effort to put fish food in his little cave in the hopes that he'll leave the coral alone. But I'm not holding my breath for it to work, which means as soon as he finishes his work, I'll be stuck staring at a dead white rock where my favorite coral used to be.
  2. zombie

    zombie Tuna M.A.S.C Club Member

    Not once for me in 5 different emerald crabs, but crabs are opportunistic eaters, so if its hungry enough corals aren't out of the question.

    Sent from my SM-G965U using MASC mobile app
  3. halmus

    halmus Cuttle Fish Staff Member M.A.S.C Club Member M.A.S.C. B.O.D. M.A.S.C Secretary

    I recently tried a trick with a drinking glass in the tank (bait on the bottom). Have it standing mostly vertical so the critter has to fall into the glass from a rock ledge.

    My nuisance crab managed somehow to drag the entire shrimp out of the 16oz glass overnight. He’s fat and happy and all I have is an empty glass.

    Maybe the trick will work for you. Search YouTube for “catching crabs in an aquarium” or a similar topic. I’ve seen it work for some people.

    Mine isn’t an emerald though. It hitchhiked in a bundle of algea and is about 3-4” across today. When I first saw him, he was smaller than a quarter.
  4. zombie

    zombie Tuna M.A.S.C Club Member

    Tasty dinner when you catch him though :). The inverted bottle trick might work with some bait. I inadvertently caught crabs and shrimp with that when I used it as a fish trap.

    Sent from my SM-G965U using MASC mobile app
  5. jda123

    jda123 Tuna M.A.S.C Club Member

    They are not coral eaters, but they will not starve. Is there enough algae for them to eat? Are you feeding them? They cannot live on poo and scavenge.
  6. jda123

    jda123 Tuna M.A.S.C Club Member

    Sinking algae wafers might be your friend.
    SynDen likes this.

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