Need some livestock suggestions

Hey guys I have an 8 gallon nano cube, That I've started to stock, this is what I currently have in it.

1 Ocellaris Clown fish
1 Peppermint Shrimp
1 cleaner snail
2 Hermit Crabs


I would Like to possibly add one more fish or something with lots of color Any suggestions let me know, I thought of a green spotted mandarin but changed my mind after some careful consideration, realizing that my small nano would have a difficult time supporting the amount of copepods he would need to sustain himself. I have 3 types of Zoas 1 Kenya tree, 1 Pulsing Xenia, a few green mushrooms, and two Greenstar polyp frags, currently this is all. Again this is my first saltwater, and I am trying to do everything slowly as patience is key, it is 47 days old, and I added the clown last saturday, and everything else was added within the past 2 1/2 weeks.

 

I would add a fire fish goby or some other kind of goby. but if you have 2 fish in a system that small you will have to be on top of your water changes. I had 2 fish in my 8 gallon biocube but it needed lots of attention. I had a lot of green hair problems, it was all over the rock and glass. it didnt really go away untill i took one fish out.

 

Yeah I do about 2-3 gallons a week of clean water, plus I run a filter rated for 50 gallons so even before my water changes my parameters are spot on, I thought of a fire fin, but I kind of like those flame angels but am pretty sure that my tank is two small, I would love something with a multitude of colors like that though