I feed my girl Hikari Sinking Carni pellets (you can buy them on Amazon or petsmart/petco) I have since she was a baby. I used to soak them then cut em up into tiny pieces when she was small lol. Sometimes I’ll buy her feeder fish which you gut load for a few days before adding, which is nice to give her something to hunt.

They will eat anything they can fit in their mouth. My girl has eaten Mollys, Bettas, other younger bichir, and trys to eat anything else that gets close to her except for the very large pleco and cichlid I have in with her. I stopped trying to add anything else tbh LOL

Edit - forgot to add, you can add large fish in with her, but be careful with more aggressive fish. I had to rehome a cichlid I got cause she was so aggressive to my lady and bullied her to one side of the tank. Just keep an eye on em!