What could I add to my 55 gallon freshwater fish tank?

[Jake1]

I have had this 55 gallon freshwater tank for about 2 years now. It has a strong filter and a bio filter. I also have an air pump. The tank is also heavily planted. These are the fish I have:

3 rummy nose rasbora
7 cardinal tetra
3 serpae tetra
1 bolivian ram
1 bristle nose pleco
2 peppered cory cats
3 angel fish

What fish could I add?

 

[JillZ]

a discus , rainbow shark, mollies , platties , blood red , glo fish , fighter male an female, many fish you an get