The jury is out on Bristle Worms…depending on who you talk to you’re likely to hear vastly differing opinions on these voracious feeders. Some hobbyists swear by them as great little cleaners…they’re happy to wander about the bottom of your saltwater aquarium after dark and feed off the debris which would otherwise foul your water, whilst other hobbyists condemn them as vicious killers who will attack and eat smaller creatures.
The term Bristle Worm covers a few different species and often they will arrive in a tank with a new order of live rock. Because they are nocturnal, many hobbyists don’t even notice their presence as they often hide during the day beneath rocks and sometimes even in pipes.
Because they like to feed on meat, Bristle Worms will spend a lot of time scavenging during the night, looking for dead or sometimes dying creatures and disposing of their remains. If this is noticed by the hobbyist, it’s easy to assume that the Bristle Worm has attacked and killed the unfortunate meal…but it should be remembered that as scavengers this is simply not in their natural pattern of behaviours and usually, the creature which is being fed upon was dead or dying to begin with.
Their presence in the reef tank is of great value due to their excellent clean-up skills and while they are not the most attractive of inhabitants, they at least keep themselves hidden during daylight hours so the tank benefits from them twofold.
If you suspect you’ve got more than one Bristle Worm resident in your tank then it’s highly likely that they have been breeding in there…this is also fine but many hobbyists prefer to remove the larger worms due to the simple fact that eventually there won’t be enough waste to feed all of the worms present.
Be extremely careful when removing Bristle Worms from the tank…those bristles can and do pierce skin so do not attempt to remove them from your tank with your bare hands. If you do get stuck with the bristles, then sticky tape is a good way to pull out the spikes! Safe removal is not too difficult though because of their nocturnal habits, it can be a little tricky to catch them!
Bristle Worms like hiding under rocks so it can be helpful to set a trap for them. A rock with a cavity inside it will make a decent trap if you pop a piece of shrimp meat inside the cavity and then place it so that no other predators can get to it. In the morning, lift the rock and the Bristle Worm will quite often still be around and you may then lift it out with the aid of a net.  You can also find special Bristle Worm traps in stores and these are effective too.
So…the question of whether Bristle Worms are good or bad is not so simply answered They’re good to a point…but larger worms can and sometimes do attack shrimp and other small creatures so if you suspect you’ve got a rebel worm in your tank keep a close eye out for it and try to remove it if at all possible.
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