(OK, 4 months isn't bad...but I'd still stick with hardier fish. )
Another good book is: Fairy & Rainbow Wrasses and their Relatives by Rudie Kuiter.
This one has tons of gorgeous, odd, colorful wrasses, many of which are smaller in size, and can be kept together without aggression worries.
A good, hardy wrasse (if you could find one, which is questionable) is the Rooster Wrasse (type of Cryptic wrasse). It maxes out at about 5 inches and flashes dramatic color changes in yellow, red, pink, purple and orange. However, it is a touch on the aggressive side, but very beautiful. My LFS specializes in weird wrasses, which is how I got mine. Perhaps you could search a few books, and ask your LFS to order you a fish you might not normally see... Mine does, so it doesn't hurt to ask.
A bluespotted jawfish would also make an interesting and colorful addition to your tank. They can handle smaller tanks, since they mostly hang out in their ground burrows. I see these from time to time at my LFS, too.