[Sk8r]

THey only 'eat' slime. They are jawless, can only suck---Leslie H, our resident invert expert in the INvert forum, says they pick up things like small [micro] food pellets by everting their mouth parts and sucking hard. They'll then take it into their den and wait for it to dissolve, I suppose, so they can slurp it up. They can do the same with bacterial slime on dead fish...slurp, that is. Eating rock is the farthest thing from their capabilities. They are excellent at cleaning, little vacuum cleaners that can go into holes where detritus gets to and few reef-cleaners can follow. If you lose a fish under the rockwork, there is very little that can match them as a disposal squad---gone by morning, instead of making nitrates for your tank.

The only really bad worms you're likely to see are eunicids, which have conspicuous wavy tentacles on their heads. If you want to ID a worm, check the head first. If you see wavy tentacles, that's a bad guy. If you see just bristles all up and down, he's a good guy.

They only get too numerous if you over feed your tank---and then you're putting your tank at risk and the overabundance of worms is saving it from the consequences: if you see anybody in the forum complaining about the number of bristleworms tell them just cut back on feeding and the population will adjust itself. If they got some creature in to eat the worms---well, you can guess: they'd go on overfeeding, there'd be nobody to eat the detritus, and all the poo from that predator would be going into the reef, too...as detritus. Bad picture. You can crash a tank doing that, at worst. At best, it's not good.

Judge the health of your tank by the worm population: about 1 small guy per gallon, good. More than that, you're overfeeding. Cut back.

If you get one of the big guys, like mine, above, [Sam, at 10"] he'll rarely leave his rock, but he'll really keep it clean. That was one of the healthiest rocks in my system before I moved and lost Sam.