I have a nem in my tank, way less time then people call for..Second this. Looks like it bubbled up in his tank. Not to mention I’ve had happy anemones in anywhere from 50 to 300 PAR in my tank and less than six months after the initial cycle.
I have started tanks and put nems in 7 days after startup without issues.. it just takes constant water parameter checking, being able to water change if needed, and keeping the cleanest water you can.
Anywho.. the nem looks happy where it is, tips are bubbled, the coloring should come back stronger over time. The biggest thing is, dont mess with it too much and dont over feed it. If it looks like it is streaching towards the light, turn it up just a tad.
They will stay put once they are happy.