Picture is kind of bad quality...
However, they look like standard button polyps. Food wise.... you don't really need to supplement them with anything as their photosynthesis process will provide about 90% of their food. But if you wanted to feed them something, you could buy oyster feast and either squirt the tank with it, or spot feed them. Personally i have a home made mix that i've blended of clams, scallops, shrimp, cod, and other misc items. When i feed my fish normally the coral grabs a few pieces as well.