Coral Suggestions

[adevice]

This is a pic of the right side of my 180 gallon.

I'm looking to add more density to what I've got, but I'm worried about the corals going to war. Everything is about 6 inches away from everything else, except the frogspawn and hammer, since I read they can be together. So, what are my choices to go in the areas between?

Also can I get an ID on the top center coral (between the frogspawn and the duncans?) :shame:

 

[cloak]

I would probably fill in the gaps with zoanthids. Another option would be some encrusting montiporas.

Can you get a closer picture of the coral in question?