It can even be done without ample space. Above is highest coral loading to water ratio test of any reef tank.
Their faces were literally smashed up against the glass and packed in from behind for nine years. It's not that one can have too much coral, it's that the disdain of the casual viewer takes precedence. People equate packed with unhealthy but it wasn't the case here. It was packed due to health and excessive growth but didn't look so good, 100% of the visible substrate is either coral, anemone or coralline. The patches on the glass are blue and brown sps shown from the base>up
The growths extend back into the tank and are stung by the corals on the rock. Inside that vase and fully obscured is a full brain coral colony which survived the blockade. Not a frag, an entire six pound rock covered in brain coral.
this guy has since been cleaned up 2.0 lol