I've seen large bristle worms attack the back side of clams,nip at feather dusters,eat shrimp while molting ,attack sleeping fish,catch the hand with glass like hair that break off when removing with tweezers,yep, placing a rock not knowing it's around the backside,some bristle toxin can itch,burn,or just throb with pain & heat.different species from different waters have ways of defending themselves along with human chemistry or allergies can vary on how they tag ya ! there great scavengers and can benefit the tank ecosystem but not your itchy hand you use for ? ...............lets say arm you put in tank the most.....:tongue1:use a stocking net or material that you can place a peice of food on ,then remove .there's traps on the market with some cool ideas but if you ever have a bristleworm explosion by the hundreds, It can grab alot at a time when the lights are out.I tried catching and tore it in two ....now two worms....segmented worms are tough to kill .I had a feather duster leave it's tube by accident ,caused by me moving a rock .It then was attacked by bristle worms that broke it into four pieces.I couldn't grab them without destroying the aquascaping .would you believe, there's four new pink feather dusters.Even broken up they still moved and then got lost,........... to emerge two to three weeks later .I'd get him out and not even put him in sump .they cling to media when cleaning.....Hey ....my hand feels numb.....too much typing I hope.......good luck deciding ?