I like it thus far and look forward to seeing in grow in more.
Well I know that I definitely want CPDs as a small schooling fish. Is it possible to add another small school of a different type in a tank this small? I was under the impression it wasn't so I searched for a good looking loner fish.Interesting to see that you and I started tanks the same weekend with eco-complete and Pagoda Stone.
Are you looking to add Dario Dario to the fauna list or replace something on the list? I'd honestly go with something schooling that is red, i.e. Boraras Brigittae. Dario Dario males show their best color when paired with a female or two in the aquarium and multiple males fight. If you're looking for a spread amount of color a school would work great and contrast with the dark substrate. If you're looking for something small Dario Dario or Apistograma's would work.
I'm not 100% sure what type of wood that is. My LFS has tons of it though. It looks more like a root if I had to guess.I was having a hard time telling last night, but is that grape vine? If so it gets a weird film over it like you have above. I tried this years ago and ended up having to ditch it.