The Bichir will probably be fine but you can't introduce him back to the aquarium. Tbh captive bred Senegalus Bichir are too small to cohab with Oscars. A full grown Oscar could easily swallow a Senegal Bichir.
Unfortunately anything that looks like a worm won't be safe with an oscar. I've seen enough pics on YouTube showing O's with skinny fish stuffed in their gob.