Bristle worms wreak havoc on all other life forms in any marine aquarium, so their removal is a high priority for saltwater aquarium keepers. Bristle worms have voracious appetites and grow quite large --- up to 2 feet in some instances. Removal is necessary to protect the other species of marine aquarium life you want to see thrive. You can determine bristle worms' presence with a surprise inspection. After a few hours of complete darkness in the aquarium, you will often find the culprits out and searching for food.
Make a homemade trap or buy one premade. Follow the manufacturer's directions if using a premade trap. Saltwater aquarium hobbyists often cite homemade traps as more effective than premade.
Cut an X-shaped hole in the lid of a plastic container with a knife or razor blade if making your own bristle worm trap. The "X" should be slightly smaller than the diameter of the worm. Push the cut plastic inward so that bristle worms can enter the baited container but not get back out.
Place your choice of bristle worm bait inside the container. One small cooked shrimp or chunk of raw clam, mussel, scallop or fish is sufficient bait to catch bristle worms.
Fill the baited container with aquarium water to sink it to the bottom of the tank. Place it in an area where bristle worms are likely to hide.
Turn off any lighting to draw out the bristle worms. They come out when it is dark and hide from the light. Change the bait food at least every 48 hours to help prevent fouling the water.
It may take repeated tries to rid your marine aquarium of bristle worms. Stay vigilant.