Absolutely aptasia. Search "aptasia removal". There are a lot of different methods to deal with them. Peppermint shrimp have worked for me in the past, but others have not had any success with them. You can also use products like Aptasia-X or F-Aptasia. I would act soon though. They can be very invasive and irritate corals. Good luck!
aiptasia are like roaches. The two you see, may just be the beginning of what you have in your system. Find a source that will continue to remove them as they pop up. Better safe than sorry.