one time i had added a fire eel and an ornate bichir of almost teh same size in length.. of course the bichir had a much thicker body and head... and i just tried them out together.. for few minut.. they swam around in the tank alright/.. but after a while when teh bichir and the eel met face to face, the eel just stared at teh bichir and then suddenly SNAP the Bichir Snaped at the Eel... but the eel swam away in time... and then from that time i had separated the Eel...
Though i have seen Bichirs and Spiny Eel mixed and livign together provided they have their own territory, their bottom space is big enough, and that the eel has to be bigger in body size than the bichir, but hten again not to big that the bichir can fit in itz mouth. =^_^=.
Happy Monster Fish All have tendancy of eating Other monster fish of smaller or slightly smaller Size =^_^=
Sorry for ur lost of Mr Eel. =^_^=