Bristle Worm a good thing? Pros, cons?

[mojojones]

Found a 6-8" long bristle worm in my tank, don't know if its a good thing or not, any advice? I know they are good, but how big should I let one get? Do they all sting, this one has obvious bristles and looks brownish/spotted in color.

[leebca]

Most advanced hobbyists and aquarists agree that bristleworms are beneficial. They churn and mix the substrate, keep it relatively clean and prevent 'dead spots' from developing.

However some of those advanced hobbyists and aquarists do believe that large ones (long ones over 6") are to be removed and avoided. Sometimes when they get very large they can disturb other marine lifeforms and risk their well being.

The above is the 'story.' I have no facts to support or refute this. You may want to post this in the Reef Aquarium Forum where they discuss invertebrates.

[Ninong]

"Bristleworm" is a common name applied to any polychaete. The very word "poly-chaete" is from the Greek, meaning many bristles. However, there are more than 6,000 different species of these worms and there is an extremly wide diversity between the various families, genera and species, as you can imagine.

We're talking about an extreme range of sizes and behaviors. Most of the bristleworms that we encounter in our reef aquariums turn out to be beneficial. Obviously there are exceptions but most are beneficial scavengers.

Some are not beneficial. It's impossible to say without a decent, clear, in focus photo. And even then it may be difficult to know for sure what you have unless you are a very good photographer with a very good macro lens and can take a very good photo of its head. A really good photo of its head. That is virtually impossible to do because it's not going to pose for you.

Usually we can tell right away if you have a bad guy from almost any halfway decent photo. We cannot do this from the description you provided above because it does not contain nearly enough critical information.