Red, orange and tan work with any bichirs species of you want to balance out the base color and the patterns. It also give some green tint color.
Black and dark brown are only good if you want your bichir to look more green. Problem is that the base color gets so dark that the patterns blends and can hardly seen. Especially lower jaw species. I don't place my PBB and lap on black as the patterns don't shows up. They may develop more green but red, orange and tan can give the same result with better pattern contrast.
White will make bichirs pale out some however remains but not as colorful. Ornate can sometimes looks good on white as it becomes more yellow.
I usually mix red, orange, tan and little of black and buff.
Also a bichir that is not skinny usually color up better than a skinny bichir. So a good diet can help too.