+1 Chichi
They need pristine, stable water conditions to thrive, and new tanks just dont have that. It looks good now, but you will go through the various algae phases and that indicates that your water is less than perfect.
They also need super high lighting conditions and im not sure you have that either.
Finally, there is absolutely no guarantee that it will host your clowns anyways. The clowns may decide they like another area of the tank better.