Lake Tanganyika Species • Introduction with pictures

[ShellGame]

Just wanted to take a moment to say hi. I have had tanks of some variety for the past 15 years or so. At one point I had a total of nine tanks but now find myself with only one 20G until I am able to relocate to a bigger house.
I am new to the shellie game as of this week but really enjoy them. Here are a few pics of the setup. I have some more shells on order.
Questions for everyone;
1. I would like to get some fish for the upper areas of the tank and would like some suggestions. Pictures of anything would be great along with how many would be ideal.
2. I would also like to know if any catfish or bottom feeders would work in the tanks.

Thanks in advance.

[Darkside]

You can include catfish if you wish, but it will limit your full enjoyment of your shellies. Danios, endlers, guppies can be included for the upper stratum if you want!