Hmmm idk not an eel expert lol I've had my fire eel 2 weeks about the same size as yours and he doesn't mess with my Tiger barbs or clown loaches in his grow out tank...
Yeah I just turned on the lights and the bichir was swimming around the top, no fins ripped so probably just checking it out. I added more pvc pipe for him since the eel has the big driftwood, and I covered the PVC with rocks and plants. Hopefully he finds it lol
Not an eel expert but im thinking the chances of a fire eel killing a bichir is really low, bichirs have pretty tough scales and are, for the most part, really hardy. I've had my 13" fire eel coexist with all sizes of polys just fine