Gorilla Crab

[mnm1953]

I have had my live rock in my tank for 5 days now. In looking at it every day i find something new. Today I have found what looks to be a gorilla crab. I understand them to be bad. What is the best way to catch this critter? I have pull out the piece of rock to look and remove but I can't seem to find this guy. I don't want to keep the rock out of water to long.

Thanks for any help.

[redwarrior77]

There are so many different theories as to which way to drive pests out of live rock is better than another. I think which is preferred depends on the person and the level of risk you are willing to take to the rest of the life in/on your rock.

1. High salinity dip. Some people like to mix up a batch of saltwater that is super high in salinity and then dip the rock in it. It seems pretty much everything in the rock runs out and then you can put the rock back in the tank and sort through the critters, adding them back as you identify them before the high salt gets to them.

2. Baiting/trapping. There are various methods to this. One involves putting baited traps in the tank itself. You can either buy these online or make your own from a soda bottle. You have to check these traps and you'll likely catch several other critters before you catch your intended prey. Another variation on this is putting the rock you know the creature is in in a bucket of saltwater with an airstone and a piece of shrimp. Then, you wait and watch for your prey to come out for a nibble and get him then.

3. Seltzer water - In this variation, you take the rock out of the tank and spray seltzer water into the hole you suspect the nasty to be in...the seltzer water drives him out and you catch/kill him.

4. Fresh water dip - this seems to be the most controversial since it has the potential to do harm to the rock more than some others. You dip the rock in fresh water (RO/DI) comes running out and you sort through it all, just like the saltwater dip.

5. The hunt - or, you can just watch and wait with a chopstick or other implement of death at the ready and try to catch the little bugger when he's out.

Good luck! :)

[snorvich]

Good advice above. Some of these I had never considered.