I can tell you what I have in my 29g biocube. BUT first I have to say I am way overstocked in this tank. Do not follow by example. LOL I am in the process of getting a 60g cube for the cube's upgrade.
Anyways, I have
2 b&w clowns they swim everywhere and keep the tank active, so good mid level swimmy fish.
1 citron goby- percher and swims here and there
1 yellow watcheman goby- stays in his hidey hole usaully half out and just watching stuff.
A firefish goby- active multi level swimmy fish
i also have a scooter dragonet and a mandarin dragonet.
In your tank I would probably get the firefish, a pair of clowns and maybe a shrimp goby with a pistol shrimp.
Inverts is where I would go crazy. lol I currently have 3 peppermint shrimp, a cleaner shrimp, an emerald crab, 1 turbo snail, 15 nassarius snails, 5 or so hermits and a couple other snails.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.