eletrocute a tank to kill a crab?

take everything living you can out of the tank.. and ammonia poison him. 5ppm might do it(6.5ppm killed 100% of mud crabs in a study, within 24 hours. 4ppm was toxic). it should kill everything in the tank. alternative, feed him, maybe tie a string on a silverside or piece of shrimp.. get him used to eating out in the open.. then spear him or net him.. I think crabs can live a long time without any food. You'll want to do a massive water change as soon as the crab dies if you do the ammonia poisoning.

i'd prefer trying to feed him and get him out in the open rather than poisoning... that's how i got my gorilla crabs.. let them feel nice and secure with months of feedings.. then bam.. out of nowhere, netted. I couldn't get my stone crabs that way though.. they were always diving back into the rocks with any movement, traps didn't work.. had to tear the tank apart.
 
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OrionN said:
Electrocute a tank to kill a crab is like nuke a city to get rid of a small time criminal. Think of something else, especially for what seem to be a harmless, and nice porcelain crab. If you get good rock, there will be plenty of hitch hiker. Don't assume that they are guilty unless you have evidence of it, or at least accurately ID it.
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The pic was a porcelain, but I found a couple that were hairy when I added the rock. Sure wish I could have a do over. One of the few times I saw the crab it was eating a snail... Good nuclear bomb analogy.

Mishri said:
take everything living you can out of the tank.. and ammonia poison him. 5ppm might do it(6.5ppm killed 100% of mud crabs in a study, within 24 hours. 4ppm was toxic). it should kill everything in the tank. alternative, feed him, maybe tie a string on a silverside or piece of shrimp.. get him used to eating out in the open.. then spear him or net him.. I think crabs can live a long time without any food. You'll want to do a massive water change as soon as the crab dies if you do the ammonia poisoning.

i'd prefer trying to feed him and get him out in the open rather than poisoning... that's how i got my gorilla crabs.. let them feel nice and secure with months of feedings.. then bam.. out of nowhere, netted. I couldn't get my stone crabs that way though.. they were always diving back into the rocks with any movement, traps didn't work.. had to tear the tank apart.
Click to expand...

This guy aint coming out in the open. When I had the trip wire trap set up, he would not enter the trap unless the red light was off.

If I used ammonia, couldn't I let bacteria break down the ammonia and then use algae to clean up the mess, rather than a water change?

heathlindner25 said:
Freaking love it!
Click to expand...

Head banging is good!
You guys are right, electrocuting is not the way to go. I was just bent at the time. I still have been trying starve the crab but collonista snails are reproducing like crazy, I imagine enough to feed a crab.

I can remove a good portion of live rock and my algae filter to save some life. I think my two best options are heat things up or use ammonia.
 
You need to go through with frying this thing. Don't let anyone else's ideas stop you from following your dreams.
 
At those levels (5-6+ppm) bacteria doesn't even form properly.. everything in your tank will die.... you'll need to lower it first... It will slowly lower as bacteria will still form, but it will be inhibited. depends on if you want to wait for a month or 2 for your tank to become stable again or not.
 
salty joe said:
The pic was a porcelain, but I found a couple that were hairy when I added the rock. Sure wish I could have a do over. One of the few times I saw the crab it was eating a snail... Good nuclear bomb analogy.



This guy aint coming out in the open. When I had the trip wire trap set up, he would not enter the trap unless the red light was off.

If I used ammonia, couldn't I let bacteria break down the ammonia and then use algae to clean up the mess, rather than a water change?



Head banging is good!
You guys are right, electrocuting is not the way to go. I was just bent at the time. I still have been trying starve the crab but collonista snails are reproducing like crazy, I imagine enough to feed a crab.

I can remove a good portion of live rock and my algae filter to save some life. I think my two best options are heat things up or use ammonia.
Click to expand...

Seriously, Joe. Draining all the water out of the tank and spraying peroxide over his rock will flush him out.
 
Mrs. Music said:
Seriously, Joe. Draining all the water out of the tank and spraying peroxide over his rock will flush him out.
Click to expand...

That's not an option because the rock structure/fake boulder was built in the tank and is too large to move or spay the underside. Plus a lot of PVC bolt holes are built into the fake boulder. But I will spray the smaller pieces of live rock when I remove them.

I've never sprayed with peroxide, I've heard soda water is also effective at flushing out bad guys. Would using either one likely kill all the good bugs, etc.?
 
You do not have to remove the LR. You remove all the water to expose the rocks. Then you pour peroxide over the rock, or squirt it into a hole or at the rock. What ever else is in the rock will be likely injured. Some good fauna will die. But other critters do not usually sleep or hide in a predators hidey hole so with luck a prized specimen is not to going to get hurt or die.
 
Mishri said:
At those levels (5-6+ppm) bacteria doesn't even form properly.. everything in your tank will die.... you'll need to lower it first... It will slowly lower as bacteria will still form, but it will be inhibited. depends on if you want to wait for a month or 2 for your tank to become stable again or not.
Click to expand...

Is regular ammonia from the grocery store OK as long as there are no perfumes, etc.? Would you expect coralline algae and other algae to die?
 
Bacterial continue to metabolize ammonia and convert it to nitrates or N2 (under anarerobic condition). Crabs are very hardy. If you get ammonia high enough to kill a crab all your live animals in it will be dead too. These rock will essentially be dead rock.
If you want to do this just take all the rock out of the tank. Soak in fresh water until everything is dead then just recycle. It is a waste of live rock. High quality live rock is of high quality from all the animals in it. That is what give your tank diversity and thus stability.
 
Good animals and bad animals are the same. Whatever kill a crab will also kill all the other animals since crabs are one of the most hardy of all the marine animals
 
I know Orion, thanks, but there's no way to get the fake boulder out. I built it inside the tank while it was empty. And if I broke it into pieces, there's no way to re-build it without emptying the tank-sand and all- and starting over. Plus, I really like the boulder as is. I doubt I could make it as nice again.

What I can do is remover the 50 lb. of really good live rock that I set on the fake boulder to finish it off and put it in a Brute trashcan with a heater and powerhead until the tank is non toxic. As much as I hate killing so much stuff, it seems like the least bad solution, if I ever want fish-and I do.

And then there's the case of the white worm about the diameter of my little finger. It was hanging out at 'his place' until I shined a flashlight on it. Then it disappeared. I wish I'd fed it and found out what it is instead of spooking it. Good worm, bad worm, IDK but kinda gives me a nudge to nuke the tank. Anyway, I'm thinking ammonia. Is regular old grocery store ammonia OK?

It's taken me so long to do this because I hate doing it. But, I will still have some life from the rock in a trashcan.
 
OMG this is a wild idea hahaha I have always had good luck getting crabs out of my tank with tall vases and Squid at the bottom to entice them. Pulled a giant gorilla crab out that way it was eating everything :-) never got the 2 foot worm that thing disappeared maybe the crab got him

Sent from my SM-J700T1 using Tapatalk
 
Getting crab out of the tank is easy. Not enough information regarding the worm to condemn all living things in the tank to death.
It seem that you are hellbent on nuking the tank. Just do it and get it over with. I get a little irritated reading your posts in this thread and likely will not add anything here again.
They way you are thinking. Why not just start the tank with dead rock and only add whatever life you know 100% safe. Nuke the tank is easy. Just replace the salt water with fresh water for several days. You better do this to all your life rock because there are lots of worms you cannot ID in the rock in the trash can. Most likely it will include the same larger worms in the LR in there too.
Certainly this thread does not belong in the Advanced Topics forum.
 
OrionN said:
Getting crab out of the tank is easy. Not enough information regarding the worm to condemn all living things in the tank to death.
It seem that you are hellbent on nuking the tank. Just do it and get it over with. I get a little irritated reading your posts in this thread and likely will not add anything here again.
They way you are thinking. Why not just start the tank with dead rock and only add whatever life you know 100% safe. Nuke the tank is easy. Just replace the salt water with fresh water for several days. You better do this to all your life rock because there are lots of worms you cannot ID in the rock in the trash can. Most likely it will include the same larger worms in the LR in there too.
Certainly this thread does not belong in the Advanced Topics forum.
Click to expand...

Minh speaks the truth.
 
Another way to go about it that is NOT a nuclear option...
Bait it out. Get a small glass wine carafe (narrow necked) and prop it steeply against rock, bait it with raw shrimp and just leave it: most crabs cannot climb glass. Repeat this until you're sure you have all your problems.

With a 100 gallon heavily rocked mature tank in which a few predatory snails got loose---I just used coral frags as bait, picked them off daily over a couple of weeks, and the problem is solved.
 
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