If the bichirs aren’t near the food as it’s eating they will be fine. If the bichir is eating towards the SAL, the SAL could suck it in and crush its skull, happened to my senegal. Or it could suck in a tail and rip off a piece, happened to my retropinnis
they were in a 55g growout until I rehomed the SAL. It was smaller than the bichirs who started out larger than it but quickly outgrew them.