Have you tested your water for nitrates and phosphates? Do you use tap water or ro/di water? I'd wanna try to get rid of the algae the natural way.
Second. Youre water has to be pristine and your lights have to be uber bright to keep an anenome. They usually don't do well in recently established tanks. Give it like 9 months and if you still want one if your lights are good maybe you can try it.
Clowns willhost anything as you can see, they dont NEED a nem to host. They can host clay pots, corals and just about anything. It's always hit or miss with them even hosting anything.
My misbars dont host anything and my b&w's dont either. They used to host an elegance cortal but it had to be removed since they almost killed it. LOL