Free reef stuff...FOR ME!!!

So I recently finished 3 years of teaching at a great private school and as a going away gift my colleagues in the science department got me a great gift certificate to one of the local reef stores. I've been patient about spending it because I just had to move my entire set up this past week. Things went well and now that things are settling down I'm already thinking about setting up a quarantine tank and doing some research on what to spend my gift certificate on.
As I hope you can see in my profile below, I have a 20 high tank that's been up for over a year now. I added a 10 gallon sump/fuge late this past winter and I've been real pleased with how the how system is running. My 3 fish (a royal gramma, a maroon clown and a 6-line wrasse) each have their own li'l niches in the tank and are cohabiting well. I'm considering adding one last fish, one that would hang out on the substrate. Any nano-flavored bottom-dwellers you'd recommend?
I'd also like to add some more colorful corals to the tank. Everything I have now, with the exception of my temperamental green star polyps tends to be of the orange-pink color variety. I know that this is partly to do with my lighting, but I was wondering if anyone had any suggestions of corals that would do well in a small tank with fairly basic lighting AND would add some color to my wee ocean world.
Thanks muchly!

 

If it were me I would add a yellow headed jaw fish, IMO. The one I have is great.

 

Oh I love the yellow watchman and the yell. jawfish is amazing, the character on them. Mine watches me and then does this hopping in and out of her den thing, and the best is when I use the sea squirt to feed her she trusts it enough to go right to the end and get fed. Just make sure you provide some empty shells around it's home.

 

What do you feed these fish and do they have to be spot fed individually? What are the empty shells for?
Thanks!

 

Yellow Watchman is definitely a good choice. Maybe try a green, Yellow or black clown Goby.
As for corals, mushrooms, and certain zoos would be a nice choice along with certain gorgonians, sponge and Octocorals like Xenia, Colt and Leathers.

 

I have a yellow headed jaw fish in my 75g and a yellow watchman in my 29g, both are great but the YHJ is still my choice. I feed them flake foods and frozen foods (i.e. mysis, brine, plankton, and small krill) if it fits in their mouth they will eat it. I can only assume that the shells are for the entrance of the YHJ's den. My YHJ uses empty shells to decorate the opening of its den during the day then pulls them over the opening at night.

 

Jawfish will also benefit from small feeders such as baby mollies and guppies. Mine tiger jawfish loved mollies.