Yeah these are the small ones and he literally has sheets of them growing on previous sheets. Great wall of dusters.

I've never minded them in the sump but when they are that successful in a display they are unsightly I think.

I have them in my sump on purpose, I was growing them to feed to my butterflies. They didn't eat them :) Given that, I'm not sure buying a fish to eat them is the way to go. I'd leave them alone.

I agree with this. I don't mind them in the sump but can get out of control in the DT and become unsightly.

These guys migrated over from the sump of my old cube tank, just basically by having other things transferred over they started popping up all over the place. Mostly in my sump, but they are starting to show up in the DT as well now. My butterfly isn't part of this collective anymore, he moved to a different tank, and he was the one who kept the ones out of the DT.

The problem I have with them is that they are a complication when it comes to wanting to vacuum out the sump. Detritus buildup happens anyhow, yes, that's why I want to occasionally clean out the sump. That stuff will cause problems to a tank as it matures if you don't keep it in check. I mean, I'm a guy who sits there with the filter sock and meticulously picks out each and every copepod that I can, and toss them back in the tank, before I toss the sock in the wash, because "these organisms are beneficial! And I rock for saving each and every one of them. Peace, love and flowers!". So inevitably what happens is I don't want to harm my "oh-so-beneficial filter feeding feather dusters" and poof, what happens is my sump becomes a huge lattice work of their tubes. The ones I have, have pretty little crowns and get to about 1" around with red highlights, but their tubes are like mud. If you touch them they disintegrate instantly into muddy water that then has to be skimmed out. And they grow, and grow, and grow (I have tubes in there that are easily 6" long) and they spread faster than aiptasia. If I clean them up and remove them, they are back to the same degree within a couple weeks. It's brutal.

It was a neat novelty at first but I really do think it's become a plaque. I feel guilty that I want to scrape them all out and flush them, but, I think it's going to have to come to that.

I'll post a picture later of my sump later on, you can have a good laugh at my expense and feel better about your own tank afterwards.

When I did my upgrade I switched position of all of my live rock (obvioously). When that happened, all the feather dusters that were growing on the unexposed portions of the rock became exposed. It seems like they like the dark spots.... no? I've been wondering the same thing... how do I get rid of these things? If they get any worse, I'm going to take action.... for now, I'm just hoping that they stay as is.

Copperband butterflies... reef safe? really?

Tony i have a huge crap load of them too. My Sump is covered and the rocks too i like them actually

I think they can be hit or miss but mine has been well behaved. Aside from ridding my tank of dusters and a couple aiptasia I had it hasn't touched my corals.

The annoying plague-like ones I've always had were the ones with hard white tubes. I used to go around my display every now and then and just shatter them all. They make the rock all sharp too and silly me thought the fish could even be scraping on them. I just don't like the way they look. If they're messing with your husbandry then axe'em =)

Darryl is correct.

In order to eliminate them (which I would NOT do) you have to control the amount of food they are feeding on. Stop the food source and you stop them from spreading. Taking them out doesn't solve the route of the problem (again, being excess food).