Bad Guys
Bad Guys

First thing to note: These guys are bad guys… If you have one, you need to try and get it out of your tank.

Bristle worms are probably the most common reef tank critter, most aquarists will encounter them at some point in the hobby. Though most types of Bristleworms (Common Bristleworms) are fairly harmless, the Bobbit is a different story.

Bobbit worms bury themselves in the sand and live rock of your tank, waiting for their prey to pass by. They will snatch an unsuspecting fish straight out of the water and into their burrows, if the fish wasn’t snapped in half before it makes it to the burrow!

Bobbit eating crab

Bobbit worms can grow over seven feet long, and often go unseen until they reach a reasonable size. If you spot one in your tank, you should remove it as quickly as possible. This can be done with a set of tweezers or with a trap. They do release a toxin that can irritate your skin, but they also pack a nasty bite, so beb sure to handle the with extreme caution.

Some aquarists will report that a bristle worm has eaten one of their fish, but it is likely that the fish was already dead or very sick. If they saw the worm snatch the fish, it is more likely to have been a Bobbit worm or a very predatory fireworm.

How do you control the numbers?

Bristle Worm Trap

Manual removal with a trap or tweezers is advisable if you have a Bobbit worm. You can find purpose built traps at several online vendors, or watch videos on YouTube on how to make a bristle worm trap.

The traps are less likely to work for Bobbits than other types of bristleworms. The best bet may be to try and bait the bobbit to strike, then grab it as it is trying to pull the prey into it’s burrow.

Do they have any predators?

There are several fireworm predators. They include;

Arrow Crab in Reef Tank
Arrow Crab in Reef Tank
  • Arrow Crabs, these are not generally considered reef safe though.

Care should be taken when adding livestock to take care of a pest problem. Once they have eaten all of the pests, they will need supplementing with other foods, or they will need to be re-homed. It is for this reason that using a predator to take care of a pest problem, should be your last resort.