Hello,
to my opinion one cannot do any better to bichirs as doing a heavy planting in the tank!
There are many reasons ...
First - bichirs love to hide.
There's no difference for them to hide in plants or under driftwood ... but plants create even more "room" for them. So they will use all areas of the tank, not only the bottom.
Second - plants help to keep your water clean! The more a tank imitates the function of a real biosphere you will get less work in cleaning ... less water changes and so on.
Third - It looks really cool!!! The look of a planted tank is more realistic than a tank without plants. The bichirs will show more action - they are feeling safer.
But if you want to plant your tank you have to pay attention about some important things ...
The Gravel - do not use sand ... the roots of your plants will rot quickly! Use fine gravel (diameter 2-3mm).
The light - i think evreyone uses a lightning system for the tank. But you have to use those special lights (mostly named "tropical" or so) - never use "plant light" for plants growing in your room! You will get an "algae explosion"!!
The "right" plants - for bichirs you cannot use every water plant ... the filigrane ones will be destroyed soon due to the bichir's action. A very good choice are Echinodorus sp. ... these plants are hard and well-growing - even under circumstances that are not as well. Anubias are a bit sensible and are tending to rot when kept in a different milieu (as they had grown before in the tank of your dealer!).
Water plants are producing a lot of O² and assimilate CO² produced by the bichir's metabolism ... perfect circle.
But one thing you should not do in planted tanks: Pumping in air with those "aquaristic" aggregats (i have never used these things in my life)! You will blow out the important CO² for the plant metabolism and cannot blow in an equivalent (!!!!!!!!) amount of O² in the water!!! For my opinion: Those air ventilation stones or whatever are as useless for a planted tank as a Harley for a bichir ...
Greetings
Uwe