fan worm/feather duster question.

[twelvejewelz]

i have a little piece of live rock with about 10-15 little what loo klike feather dusters. they are as thin as a pencil point and about a half a millimeter long. the fan part is a flat fan not a round fan if this makes sense. will these one day grow to be a normal size say 3-5 inches or are they a small species?are they good or bad? i would take a pic but they are really to small to capture with my camera.thanks

 

[dendro982]

Flat 3/4 of the circle fan, oriented sideways continue to be small, flat funnel shaped - depending on species - will grow to fan 1" in diameter and reproduce fast, horseshoe shaped will continue to be small. I had no problems with either of them, apart from fast reproduction of the funnel shaped ones and when they settled where I don't want them to be