Any of us that have kept bichirs for any length of time have at one time or another had this happen! It's a real bummer! They are indeed the world's best escape artists. They seem to really try to escape when first arriving or when moved from one tank to another. I was lucky enough to find one that had been out for probably 6-8 hours, but put him back in the tank and swished him around, trying to get a water flow over his gills artificially. Surprisingly it worked. Since then I always put them back in the water even when they seem dry to the touch! Sorry for your loss!