What's this? Is this a hydroid?

[concept3]

http://i9.photobucket.com/albums/a74/concept3/for%20sale/what-is-this.jpg


I originally thought they were some kind of feather dusters, but after a 3 month growth explosion in my tank, they seem to be making the SPS they touch aggravated to they point where the polyps recede.

It looks like they are harming the corals, how do I rid my tank of them, and any suggestions on natural control? (fish/inverts) I've already taken a lot out with a pair of tweezers, there are a lot more out of reach~ thanks in advance!

[Diablitaroja]

I've got something very similar, and though I've never had them really harm corals that I know of, I'm not sure that the clumps I have are really near any corals anyhow -- but I agree with you that they could be hydroids or maybe tube-forming "snails" (like vermetids, judging by the mouth parts) of some sort. If they are hydroids I hear they thrive on nutrient excess like pest algaes and whatnot.

I haven't tried it (what little help I am!) but I've heard butterfly fish are good for some types (of hydroids) and sea slugs for others, your best bet would be to try to identify exactly what type you have and hopefully be able to match a specialized slug/butterfly.

Best of luck! fwiw tweezers have been my first line of defense as well and I've held my ground to an acceptable level to this point ;-)

Red

[Tu Ku]

Definately yes, a hydroid. Not good in most opinions. Good luck, those things suck.