We've been experimenting with this starter tank for about 6 months now.
So far we have:
oysters (they help filter the water)
1 seahorse
1 Rock Bass (that's him under the sea horse hiding)
1 Sheeps Head (left bottom)
1 Some type of Red Grouper (he's hiding in their hole behind the rock bass)
1 Pig Fish (he's hiding too, lol)
a few snails
Most all of those small minnows you see at the top will be eaten by morning.