Possible Comb Jellyfish

[Oldtimer65]

Hi. Just joined but have been following all the good information on this site. I have a 16 gallon Biocube that has been set up for about a month. I have noticed a few of this sedentary guys hanging in the hair algae and recently they have exploded in population. I have removed rocks to pick off as much of the algae and have cut back on some of these guys but concerned if anyone thinks they could be a problem for any other things like fish etc that I may want to put in. I believe they are Ctenophores or comb jellies. They send out two very fine tentacles with tentilla from 2 knobs on their bodies and collect debris from the water column and then pull the tentacles back in. I’m including a few pics to show what I have. Please let me know if anyone has experience with these guys.