Help ID. Featherduster or Paly or what?

bh750 · Feb 1, 2023

So I have a 220g tank that Is very mature several years but only one coral in the tank, am guessing they are Polys - see below first picture.

Then I've just started getting these smaller, feather duster type things popping up in clumps. Look like feather dusters but they don't retract like feather dusters when touched. Could they be the Palys spawning? See 2nd pic.

Soren · Feb 1, 2023

It's hard to see in the picture (a better picture under white lighting might help) but you might want to look up hydroids as well. From what I can see, that seems to be a possibility for the second picture.

The first picture looks like Palythoa to me.

Tired · Feb 1, 2023

Those are palys, and they are the extremely toxic kind. You shouldn't be handling any rocks barehanded (due to sharp edges and nasty bacteria), but be especially careful with those, especially if you're doing anything that could irritate them.

Agreed that the second picture looks more like hydroids.

vetteguy53081 · Feb 1, 2023

Cant see anything due to brightness. My hunch is may be hydroids which is typical but please provide side shot instead of top down.

bh750 · Feb 2, 2023

Oh boy. thank all! They are definitely Hydroids. Never heard of these before. So bummed theyre a best and not a nice coral! Theyre so pretty too. Weird b/c I havent havent added anything new to my tank, but did improve overall conditions and water quality so maybe thats it. Also just happened to get an aquacultured File Fish from Biota to help keep aptasia in line (after these hydriods spouted up). Maybe he'll eat those too.

Tired · Feb 2, 2023

Some hydroids are pests, but some keep to themselves and don't bother spreading out of control. Likely nothing to be too worried about with these guys.