Before endeavoring to remove bristle worms from your marine aquarium, determine whether the worms in question are harmful or beneficial. "Bristle worm" covers many genera and species. Most feed on aquarium waste and detritus. Some opportunists attack injured animals. A few are predators of healthy invertebrates and fish. You need to remove predators; you can leave scavengers in peace. Several strategies exist for controlling bristle worms.
Don scuba gloves. Turn off lights in the aquarium and in the room, which should cause bristle worms to venture forth to feed. Turn on the flashlight. When you see a bristle worm, nab it with your gloved hands or a net. You may need to remove chunks of your live rock from the aquarium to extract bristle worms with tweezers.
With a hand drill, a quarter-inch drill bit and a vise, drill several holes into an 8-inch length of 2-inch-diameter PVC pipe. Place fresh seafood bait such as shrimp inside the pipe and cap the ends with removable caps. Place the baited, capped pipe inside your aquarium at night. Remove the pipe in the morning. Remove an end cap and dispose of the trapped bristle worms.
Place fresh seafood bait in a nylon stocking. Tie a knot in the stocking above the bait. Secure the baited stocking inside the aquarium. Feeding bristle worms will become trapped in the stocking's fine mesh. Dispose of the stocking with trapped worms.
Siphon several handfuls of your substrate into a shallow casserole dish along with a length of aquarium tubing with a diameter of 1 inch at a minimum. Don scuba gloves. Comb through the substrate with your gloved hands and remove bristle worms with tweezers.
- 💡 Inspect all new live rock for bristle worms; remove them before adding the live rock to your aquarium. Many fish and crustacean species eat bristle worms, including arrow crabs, wrasses, puffer fish, sand perches, dottybacks, trigger fish, coral banded shrimp, gobies, gruntfish, hawkfish and dragonets. Many of these animals will also eat your expensive pet invertebrates as well, so add them to your tank with extreme caution.
- ⚠ Avoid killing beneficial burrowing polychaete worms. Like predatory worms, these harmless animals enter your tank in live rock and sand. They improve the health of your aquarium by removing decaying matter. Harmless polychaetes are often falsely accused of killing fish and invertebrates when they scavenge tank inhabitants dead of another cause. Be sure to confirm the identity of your bristle worms before removing and killing them.
- ⚠ Actual predatory bristle worms typically have venomous spines. Always use scuba gloves when handling them.
- ⚠ Decaying seafood in baited traps can kill sensitive marine invertebrates. Place baited traps in the tank for only a few hours at a time. If you use them overnight, remove them first thing in the morning.