I've got CRABS!

Discussion in 'Inverts' started by blackraven1425, Apr 12, 2010.

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  1. blackraven1425

    blackraven1425 Giant Squid

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    Ok, so, when I got my rock originally, I got it from a Florida aquaculture outfit. I went with them because of the awesome diversity of life, and I'm still loving a very large portion of the stuff on there. I just realized I have about 20 mussels, which surprised the heck out of me because the "rock" moved when I put my arm in rofl.

    Anyway, originally, I dipped all the rocks in FW, and got about 30 gorilla crabs off of it. Then, a month later, I saw 2 really big ones (about an inch and a half), got scared for Riddle (the occ. clown, he was like 1" at the time), and couldn't catch them in the tank, so I pulled all the rock and went with a turkey baster with fresh water, a pair of chopsticks and a flashlight, and got rid of about 65 more from the rock. I had 2 porcelain crabs that I found, and decided to leave them in the tank, as they shouldn't tend to be nearly as bad as most other crabs, being filter feeders and all.

    About 5 days ago, I noticed one head of my new frogspawn coral shriveled up and couldn't figure out why, so I looked at night to see if the torch might be bothering it, as it's in the general direction of the flow. When I looked, I saw a gorilla crab, killed it, and fed its corpse to the cleaner shrimp - who really dug it.

    Now, for the past couple nights, I've been killing 2 or 3 crabs each night, which is scaring me - this is how many I killed per night when I had at least 60 of them on the rocks, so there's likely a decent number around the tank.

    So, I know that my rock is totally bad for being aquacultured, and I'm nearly at the point of regretting the purchase because of the darned crabs. I've asked this question at a couple LFS and Petco during the last outbreak of crabs, and nobody came up with anything, but I'm giving it a shot here:

    Is there any shrimp other than a mantis shrimp that loves hunting crabs? I know my cleaner and coral banded absolutely love it when I crush one of the gorilla crabs and give it to them; it's their favorite meal, right up with mysis shrimp. I don't think they actively hunt for crabs, though, so I'm wondering about other options from a group of animals that can't resist crustacean meat.

    I'm asking about shrimp that aren't mantis shrimp because I really don't want a shrimp that's too smart for a trap to work, I don't want them to even have the possibility of breaking the glass of the tank (very young kids are in the house frequently, so they might end up doing something a mantis sees as a "taunt"), and if this is possible, that won't completely eliminate the crabs. I'd prefer the shrimp/other invert to be a long-term solution, keeping the crabs to a low level so they're not really so much of a pest, but enough so they have a continual food source and aren't at plague proportions. If that's not possible, total elimination would work too.

    I don't really want it to kill the mussels and barnacles that are all over the rock, but if they have to go too, so be it - the tunicates and sponges are starting to grow a whole lot the past month or so, and can pick up the slack.

    So, now that you've read the diatribe (maybe), any ideas on a very specific shrimp, or do I have to get out the chemistry kit and start splicing genes?
     
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  3. elweshomayor

    elweshomayor Giant Squid

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    well i really cant help you there.. thats a though one.. other than replacing all your rock for simple base rock.. but im pretty sure thats not going to happen. so i guess this can be a bump to your question so maybe someone else can help you. good luck :)
     
  4. dumbderk

    dumbderk Purple Spiny Lobster

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    If you dont have a large snail populus and your shrimp that are already in the tank are very fast, get a small puffer fish they love that stuff. Maybe do a little research on that type of crab and what its enemies are.
     
  5. dumbderk

    dumbderk Purple Spiny Lobster

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    How big is your tank? I heard that Golden Eels and a Zebra Moray are pretty good with crabs and are reefsafe with caution, they will however eat many small fish but the zebra has very poor eyesight and will usually eat anything that gets between him and the meal so basically its a chance type of thing, if you got small fish that are precious I would make sure they are fast and have plenty of hiding spots.
     
  6. Telgar

    Telgar Snowflake Eel

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    I think a quick 2 minute soda water bath might help, it's just carbonated water and should not hurt the mussels etc since they will just close up and protect themselves but should send the crabs running.
     
  7. blackraven1425

    blackraven1425 Giant Squid

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    Well, I sprayed freshwater into every little nook and cranny the first time around, and dipped for a minute, and it seemed to have worked until 5 days ago, but really didn't in the long run. I'm guessing I happened to miss at least 2, that happened to be a male and a female. I would try with soda water, but nearly every coral I have in the tank is epoxied to the rock, and would make this a much more intensive process than it even was the first time around.
     
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  9. Telgar

    Telgar Snowflake Eel

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    well, that certainly sucks. :(
    This just reinforces the reason I started with 100% dry rock.
     
  10. blackraven1425

    blackraven1425 Giant Squid

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    Yeah. I mean, I don't really know if I consider it a good decision now that the crabs came back. I really do like having a bajillion filter feeders (barnacles, mussels, sponges, tunicates, sea fans, mini dusters.....it's really like every kinda of feeder imaginable, with some you really can't get from dry rock) everywhere, but the crabs are annoying. If I put in a mantis right off the bat, and let the tank sit for a couple months like that, I would absolutely say that the aquacultured rock would have been the best decision, but now, I don't know.
     
  11. BonnieC

    BonnieC Astrea Snail

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    I think you just convinced me not to get LR like that...mantis shrimp give me the heebie jeebies! lol
     
  12. blackraven1425

    blackraven1425 Giant Squid

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    lol. I kinda have a thing for shrimp in general, they're awesome animals. I think mantis shrimp are the coolest things, I just really don't like the thought of my entire tank on the living room floor.