central area of the fish tank not filled!!!

[l3y3w2]

i have silver arowana swimming at the surface of the water and bichrs swimming at the bottom, but the middle part of the tank is empty, im looking for good looking fish to fill the spot that swims at the mid water level . knife fish might be it, i need some advice besides knife fish what are my options

btw its 48 x 21 x 36 100gallon tank

 

[Amphilophus88]

A medium sized cichlid?

 

[ecoli73]

flagtails

 

[erk419]

Tinfoils or silver dollars. Is this a grow out tank for your Arowana?

 

[l3y3w2]

my silver arowana is baby size.. 4inch