I think you folks are giving bichirs way too much credit! These are VERY VERY primitive fish, that swam back in ancient times! Another word for primitive might be highly un-evolved. Very small brain capacity. I hate to use the word STUPID but there you are! Most of their thought processes are probably "can I eat you, or can you eat me?" What you're deciding is familiarity or somehow bonding with you is just your bichir figuring out you're not a threat. Nothing more, nothing less! They have survived eons because they've developed a skill at hiding and have a quick flight response! WHEN UNSURE--LEAVE! These are wonderful and interesting creatures, but don't make them something they're not! IMHO