Depends on the species of Bichir and/or if it's temporary or a permanent situation. If it happens to be one of the smaller upper jaw species, I would worry about the Convicts bullying them as they mature. If it's a larger species of Bichir, over time, it's a good possibility that the Bichir will eat the Cons, if the Cons don't bully them too much. I'm not saying it's impossible as I'm sure other members have had this combination with success. My experience is that Cons can be overly aggressive and can harass any fish. Even with plenty of hiding spots, the best thing is to have a large tank for either species to escape one another.