I just wanted to post up a huge thank you were settled on the pearl gourami and rasbora - tank arrives Friday so time for us to look into the environment suitable rock/plant/wood supplier and the right types the soil/gravel is now a priority and knowing the fish should make that easier.
In the aim of regenerating the environment im thinking ecocomplete (red), a scatter of small rocks with one/two large, then the back planted opposite the big rocks more heavily planted.
I would not use the EcoComplete. This so-called enriched plant substrate has issues. Primarily, it is sharp for fish, and while substrate-level fish haven't been considered so far, they might be later, and this would not work. Secondly, this does not benefit plants in my experience. Third, the red colour is a distraction when you have the intended fish. A better substrate would be neutral, in the grey/buff mix category. I would also use sand, again just in case substrate fish enter the picture later.
The species being considered inhabit swamps and slow-flowing streams in blackwater regions (in case someone spots it, there is one exception for T. espei, just so you know that I know). Play Sand with a layer of dried leaves, chunks of wood and branches, would make the perfect aquascape.