Neomeris sp. Not really thought to be aggressive but it can spread. I have seen it in many of my tanks. I usually pick it if a see a few stalks growing and it will keep it at bay i have found pretty easily.
29g Mixed Reef, 150w 14k Phoenix MH w/ Moonlights, Reef Octopus BH1000 HOB Skimmer, Ecotech Vortech MP10es, ReefKeeper Lite (Plus), PH Probe, Temp Probe, ATO, Carbon/GFO Reactor.