Help Id Feather Dusters? and Sponge?


Reefing newb
Can anyone tell if these are some kind of feather duster on top of the rock and in the center of the rock there is a Gelatinous growth with what looks like vent holes in it, is it a sponge I had this rock for almost a year nothing growing it on has spread or jumped to other rock! I just want to know if they are what I think? What I believe is a cluster of feather dusters are bluish green when I turn the lights on in the morning then changes to a greyish red after a hour or so. They do close up when disturbed and the fish avoid them.


  • IMG_1130.jpg
    170.7 KB · Views: 615
  • IMG_1131.jpg
    129 KB · Views: 585
  • IMG_1133.jpg
    130.7 KB · Views: 413
Last edited:
I can't really tell looking at the pics on my phone but look up aiptasia, mojano and colonial hydroids to make sure it isn't one of those pests. The other thing you described sounds like a sponge.
Could be I just looked for photos of Hydroids and they all have soft stems these guys live in a hard tube that are very strong the rock has been knocked over and landed on their tubes and none of them broke I will try to get a better pic but my camera only has a zoom lens on it and cant focus any closer. but if they are Hydroids are they a problem?
Yes, colonial hydroids will spread quickly and kill anything they touch. They are hard to get rid of as well. If they are only on one rock, I would remove it from your system and dry it out for a few months. Just my opinion. Im sure others will have suggestions. Do some research on them and see what you can come up with.
I Think I got it before it spread it was a new Live rock from my LFS I purchased exclusively for the refugium, I might have gone overboard but I threw it in the Oven and baked it :death: (The Rock) for and hour at 425 LOL then put the dry rock in my curing tank the next day, I have not seen the critters again, so I hope it was isolated to the one rock, I will not buy anything live from that LFS again he does not take care of his tanks after going back to look around again I found the same critters in the tank he pulled the rock out of :shock: he has been business for 30 years and told me I am doing everything wrong? such as not using Damsels to acclimate my tank so anyway thanks everyone for your input! I am new with Salt Water I got bored of African Cichlids after raising them for 20+ year.

It sure looks like apista. If so your in for some trouble. Those things spread like wildfire killing everything it touches. I hope you get it under control soon.