Zoas can be placed high, yes, even close to the surface of the water. It is necessary to adapt them to such light. Any light. If they are brown they've go too much zooxanthellae.

Why are my corals turning brown?

The Cause: Corals typically turn brown as a result of the overproduction of zooxanthellae (a type of algae) inside of a corals tissue. As zooxanthellae levels increase, they block the coral's natural pigments causing them to turn brown.

How do I know if my ZOA coral is dying?

Usually a zoa will shrivel and disapear pretty fast if its dead. Visit SIR PATRICK's homepage! rotting flesh, brown black color.