hydroids? what are these pests

[AmazingYocool]

an ammonia spike must have happend, which caused my nutrients to be unbalanced and all of these came out of seemingly nowhere. idk if its hydroids or small aptasias. they have clear circular heads and long hair like tentacles. any biological (fish or invert) ways to remove? ty

 

[Elira_6301]

Those look like hydroids for sure. I would suction them off. Thats what I do with aiptasia. I use a syringe and get super close and suck them right off.

 

[Elira_6301]

I read peppermint shrimp may help.

 

[BriDroid]

Those look similar to the hydroids I had when my tank was young. They seemed to disappear as my tank matured. I did dose coral snow to starve them. I also had a tuxedo urchin that would eat them as he was grazing. I also noticed bumblebee snails would eat them, albeit very slowly.