How to remove hitch-hikers without killing them?

[blugar44]

Just about to set up my 150 gallon reef tank. Currently cycling 55 lb of live rock in a separate container of saltwater with a powerhead, heater and filter.
At night with a flashlight, I've spotted a small transparent snapping shrimp, two 1" hairy crabs, plenty of turban snails, a few filter feeding sea cucumbers, copepods, amphipods, bristleworms, you name it. I'm also fairly sure I've seen one aiptasia anemone which I'll have to think about removing.
My question is how to remove these hitch-hikers before adding the rock to the tank once the ammonia and nitrite has disappeared? There's definitely some beneficial critters in there such as the copepods, snails and even bristleworms to some extent. I also want to add the crabs and shrimp to my fuge as cool little sump monsters.

I know about the hypersalinity method, and I was wondering if this kills the critters? I'd love to just be able to shake all the hitch-hikers to the bottom of the bucket and pick and choose which ones I want and don't want with a pair of forceps.
Thanks!

 

[Betta132]

The snapping shrimp is harmless. Pistol shrimp aren't physically capable of killing anything larger than a tiny worm. I'd suggest leaving it in and letting it do its thing, at worst it'll shoot a couple of amphipods. Even big pistols can't kill stuff with their snap, it's mostly used to make scary noises and discourage intruders.
The cucumbers are also harmless.
I'd suggest leaving the bristleworms alone, they're useful.
Try a bottle trap or two for the crabs.

That'll catch anything that'll crawl inside. You'll get crabs, pods, bristleworms, maybe some snails, and the shrimp. I do suggest keeping the shrimp in the tank, he can't defend himself against crabs and will probably get eaten if you put him in the fuge with your other little beasties.

 

[blugar44]

Thanks. I keep finding gorilla crabs; almost a new one every night. One I've become quite fond of as he has obviously grown since burrowing into a crevice in the rock and now can't escape, so I'll give him a tiny piece of peeled prawn with tweezers and he'll desperately try to reach it with his claw through the small hole. He shouldn't be too hard to catch at all. It's the others I'm worried about that are free roaming.
So should I just cut the top of a soda bottle off, invert it and stick some prawn inside?
Hopefully that should work. Definitely makes it easier that these rocks aren't in my tank yet!

 

[Betta132]

Better get some pliers and break away the rock around the trapped crab's hole before he sheds again and becomes hole-shaped!
That's the basic idea. I'd suggest setting up a few smaller traps, too, to catch small things. Also, try a few different baits, and put the traps all on strings so you can haul them out without reaching in and scaring everything. I'd also suggest waiting by the tub for awhile the first time you try it, so you can haul the traps out as soon as you catch something. Once you get all the dumb stuff, leave them in for awhile to catch the smart things.
Oh- if you intend to leave the traps in for more than an hour or so, be sure to poke them full of tiny holes to allow a bit of circulation.

 

[Calappidae]

Tank of the apes? Gorilla crabs are everywhere it seems.

Those are definitely bad guys, everything else (cucumbers can be toxic upon death sometimes) is pretty harmless/benefical. Have you seen the pistol shrimp or only heard a click?