delhezi bichir

Could I add a delhezi bichir in my 75 with my roughly 6 inch senegal? If so how big would I have to get a dehlezi for him to be safe? Current stock: • 1 6 inch senegal bichir • 1 4-5 inch zig zag eel • 2 synodontis • 1 banjo • african butterflyfish • 4 red ruby barbs ( prob getting rid of) •...

Both are delhezi....lighter one has been there a few days but color doesn't seem to be changing. Anyone else have same species bichirs with such large difference in color?