Until half of your substrate is covered with bichirs lol. I guess your bichirs are still small so it looks kinda empty. How many do you have now and how big is the tank anyway? Oh yeah, get some driftwoods and larger plants.
I love driftwood in my tanks, so you could definitely put some in to spruce it up. If you are worried about the tannins (makes the water brownish) you could just boil it so that all the tannins leach out or soak it in a bucket of water replacing the water daily until the water is clear.
Some plants would also be nice. I like plastic (instead of fabric) because they are easier to clean. A nice background would also be great.
If your gonna go full on bichir then put a backround up, some BIG branchy driftwood, and some live plants... If you do plants yer gonna hafta bail on the sand and get some proper substrate, the darker the better...
i would go for a shaped 3d background , a nice centre branching peice of driftwood then smaller peices of driftwood in corners surrounded by some good quality fake plants , but hey every-ones preferances are differant ,have a look through the gallary and take bits of insperation from diferant tanks you like the look of to come up with your individual tank , good luck