Thanks! I looked at the thread, and it has a few good ideas, but nothing that really jumps out at me.
My latest fish obsession has been peacock gudgeons. I was thinking that they would make for a BEAUTIFUL addition to the 6 harley's (I have 6 now, as there were 3 that came with the tank, I felt I needed to flesh out that school so I got another 3) and RCS colony.
My latest concern is that this is a 20 high, so I want to spread out my stock vertically... and right now I'm noticing the harleys spending a lot of time in the bottom 5 inches of the water column. I don't remember them doing this before when I've kept them, but that was quite some time ago.
I've decided against gouramis, and have been looking into neon dwarf rainbows or threadfin rainbows over the past week. I think that 5 dwarf neons probably would be too much, but a small group of threadfins wouldn't be too bad.
Latest idea:
2x Peacock Gudgeon
5x Threadfin Rainbows
6x Harlequin Rasboras
12x Cherry Shrimp