I've been waiting for something like this to happen in my tank ... I've only the one senegal bichir (5 1/2" - 6") and I was hoping he'd devour the few fish that were in the tank. But I'm starting to think he's off all live foods now ... (I'd stopped feeding him live foods for awhile there). I've 2 platy's and 3 cherry barbs still in the tank from when I established it, as well I've added 5 ghost shrimp about a month and a half back, and my bichir has left them all alone. So like it was previously mentioned you never know.
But it has helped build my confidence about putting African Butterfly Cichlids in my tank like I was hoping.