If it's aiptasia they'll grow pretty quickly and you'll be able to tell for sure. Give it about a week, they grow like weeds. Once they're a little larger you'll know for sure. If they are aiptasia, Blue Vet makes stuff called Aiptasia Control. It's a milky liquid you squirt on them with your pumps off, they melt right away and it's reef safe, won't hurt your soft corals. Really cheap too, I used it in my nano when I got some aiptasia (i have a coral banded shrimp and he won't eat aiptasia but will eat other shrimp), works great.