i think there are many reasons that take influence to the coloration ...
First i think the tank interior take influence - i have a very rich-planted tank. So the bichirs do have many hiding points - especially in the plants ...
... i also use dimmed light - bichirs do not like bright light at all ...
... especially my Lapradei goes through many coloration phases. Now he is very bright, at night he looks more like an ansorgii - a few weeks ago he had those vivid green patterns. What's next? ...
... i think the food will also take influence to the bichir's coloration. I ffed them with feeder fish, fish filet, earthworms and sturgeon pellets ...
great photography skills
and i think most of your polys have the greenish tint because of the extreme planted tank of yours
had seen a pic of your tank long back
how about an update pic again
Great sollection you got there. Especially like the Polypterus teugelsi and weeksii, both are very nice. You got a unique senegal too as I seldom see one with green spots.