Bristle worms are not bad -.-

Fireworms ARE bad.

I don't understand why every one thinks there bad. I remove large ones. But large to me is like pencil size. Other than that they come and go depending on wasted food in tank.

Please tell us why they are so bad

And heads up on an arrow crab, you might lose snails as well. They are like any crab, opportunistic... when worms run out, snails tend to go missing.