Definitely looks similar to gracilaria but it’s much, much finer than species of gracilaria I’ve seen. I’d say the little frills are about 1mm across. Also must have a way of reproducing via some kind of spawning because it’s showing up all over the tank. Definitely getting a little nervous, especially since this is a planted tank with higher than normal nutrients. I may have to add some additional macros and see if I can get them to outcompete this stuff.