String on base of acan

[Nathd2311]

Could anyone tell me what this stringy stuff is on the base of my acan. It seems to have been receding this past week or so after doing well for months

 

[Timfish]

It's a sponge. It's probably covering a lot of the underside of the polyp. It's very beneficial for the ecosystem but bing in direct contact with the acan it might irritate the acan a little. You can gently pull it off if it bothers you but I would leave it myself.