Spotted this in my sandbed and swiftly moved to scoop.it, and the closely surrounding sand out of the tank, succesfully. But should i still be concerned? I have not added anything to the tank since April. But I've been letting the tank coast aside from the occasional feeding and spurratic water changes. I guess my question is, is this aiptasia? Do I need to investigate further for an infestation if I see no other aiptasia in the tank?