20 gallon choices?

What are some nice fish to add to a 20 gallon fowlr currently stocked with: 1 ocellaris clownfish, 1 firefish
I want to add a ton of life to my tank, but need some more choices.:-/

 

possum/pink streak wrasse and royal grammas.

 

yea I was thinking about the pink-streaked wrasse, but is there another choice or option like a fish that groups, but maybe doesn't grow big?

 

Orange lined Cardinals are way cool in groups of 3 or more. Pygmy wrasse, Tailspot Blenny, Yellowtail Fang blenny is a fav of mine cause I own one Good luck and have fun shopping!

 

I wouldn't get more than 4 fish unless they are very very small. Smiths fang blennies are cool.

 

If you want a bottom dweller look at a yellow goby, super cool fish.
Or if u can find a tiny diamond goby, they're beautiful but get
Pretty big, hence why u need a small one.