I try to pluck all the Caulerpa i have but it is getting tedius. Is there anything that will eat the feathery type Caulerpa? All my grape type are gone but I can't get rid of the feathery ones.
Caulerprin is a toxin in these seaweed, and most fish/invert will stay away from it. Some may nip on it and spit it out, helping it to spread all over the tank, and some reports that their rabbitfish/tang/etc do eat it, but not IME.
I once had a foxface that would eat anything green, including caulerpa.
I'm guessing certain varieties of it have more toxin than others, but who knows, the fish also has venomous spines, maybe they're able to deal with the toxin a bit differently. However the Foxface is not a small tank type of fish, and I have only noticed the serious algae decimation of it when it was quite large (6-8 inches guestimate)
i've heard of foxface, in particular, eating all types of caulerpa. try an algae grazing urchin like a pincushion, longpsine, or blue tuxedo urchin. the urchins will also eat coralline, just so you know.
my tangs eat bubble caulerpa like it's their favorite meal, but i don't know about the feather variation.
they will also eat very small sprouts of hair algae, but they won't touch it once it grows full and long. it must get nasty tasting at that point.