Cool, you got some Bichirs. Just 1? What store did you pick them up at? When you upgrade tanks, and if want to get some Endli’s let me know, I know of a place you can get small ones 5-6 inches for about $35 (they have to special order them).
I currently feed my bichirs catfish pellets, earthworm sticks, soft moist frozen shrimp pellets (these three are from Ken’s fish), Hikari Sinking Gold, and market shrimp (once a week). My larger Endli’s have grown huge with this mixture of food, they were smaller than the Laps and Ornates I got from others at a larger size, and both are the same size as them or larger. Thickest one is about as thick as a ½ inch PVC connector.
Throw in market shrimp (uncooked) into your mix of food along with the silver sides. You can start off with the smaller frozen shrimp which is usually cheaper, try getting from a Asian Store or Winco. You can usually get anywhere from $3.99 to $7.99 per pound. Thaw them out in warm water remove the shell and cut it up in half length wise (so it isn’t too thick) and depending on how long maybe cut again the other way so it’s not too long for it to swallow.
Post some pix of your tank and fish.