Bristle worms - friend or foe?

7 May 2007
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Hi All,

I have just discovered quite a few bristles in my and orange in I have heard several ppl. say they are not harmful and actually beneficial, but then I get articles like this below:

Bristle worms can be, and usually, are a real problem for reef hobbyists. Indeed, they create havoc in the aquarium, especially when they grow to larger sizes. Bristle worms grow quickly! Real quickly! They feed on anything they can find in the tank and grow to sizes that amaze most hobbyists. This process does not take long either.
Whereas small bristle worms may look really harmless, larger specimens that have grown to sizes of 24 inches or more in length are quite impressive and can cause serious damage. Remember too that the size you see is not necessarily the size of the worm. It may be retracted and look short and thick, but it can stretch itself to a real long size and be very thin. In either case it is a voracious eater. In addition to feeding on left over food small crustaceans, and detritus from which they extract uneaten parts, bristle worms attack corals and sometimes other animals too (anemones are a good example of the latter). Because of the damage they do, they absolutely need to be physically removed from the aquarium. - Net Pets

So, could anybody pls share sum light on this for me, 24inch worm in my tank is kinda creepy, considering the proximity of the tank to my bed, i see a B-Grade Horror movie coming on...


A worm that large could be a problem, but generally they are not a problem and i guarantee most of us have them in our systems. The older train of thought was that they are harmful and get rid of them the newer thinking is they are good detrivores. But personally i would not take a chance with one that size.
I'm sure that that is a very old article. Bristle worms now considered good. Only very rare species cause probs.

They are friends.
granted the ones in my tank are just under a cm. so nowhere 24inches, fair enough, I'll let them be. (truth is at under a cm i was not planning to go near 'em anyways)
What is the problem is generalisations....Saying that bristle worms are a problem is like saying that fish are a problem when all you have looked at is damsels. There are thousands of different species of bristle worms. Amongst them are certainly species that do attack corals. I would suggest that these are a very small proportion of all the species that we have. If you are uncomfortable with having a bristle worm that large in your system. take it out. As Bob says though, most of the worms (and you would be surprised how many you have in your system if you did a throrough search) are harmless and beneficial to your system.
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how do we tell the difference between friend and foe in regards to bristleworms?
lol @ Alan.

I like my Bristle worms :) If you keep up your system maintenence and have a good nutrient removal regime britle worm populations will stay manageable and be beneficial.
When they reach plague proportions they can become problematic.

You can also add one of the halichoerus species of wrasse that will bioligically control the population ;)
I read a while ago that it is mostly the fire worm that is a problem.
No, but they are very similar to the normal bristle worms, except they are a pinkish red colour.
Check your system at night with a torch, you will be surprised at the amount of worms you have.
... so, could anybody pls share sum light on this for me, 24inch worm in my tank is kinda creepy, considering the proximity of the tank to my bed, i see a B-Grade Horror movie coming on...
Although there are a few carnivorous species, *most* bristle worms (including many "fire worm" species) are detrivores/scavengers, and assist in keeping your tank clean. They WILL eat dead or dying organisms, and that is where their bad reputation probably came from... If, in the past, you had a dying coral in your tank and you found some worms in/on it, you would have blamed the worms for killing the coral, as you would not have known any better. Today, we know that the worms most likely did not kill the coral, they only did what vultures do on land... eat the dead/dying animal before it could decompose and kill your whole tank by polluting the water.

If you really don't want that large worm, I will gladly take it from you - in fact, I would even pay you for it...

Best way to tank watch at night is to use a torch with a red plastic or filter over the lens. Nothing even knows your'e looking.Just use a piece of plasic thats red.I think BW's are benificial to a point but if they are too big (10cm+++) then they can be destructive.Cheers
Sell it............. LMAO. Reef Maniac offering to buy it??

Now I've heared it all

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