Best qualities for Green Star Polyp?

[FindingPonyo]

Hey! I have green star polyps. Once I got them, they turned brown. Not unhealthy per se, it is still growing but the color is not as eye-pleasing as it used to be. What is the best temperature, flow, lighting, etc does it need? Do peppermint shrimp eat it?

 

[PanchoG]

They like flow, and normally do directly in the substrate.