i agree with anne,
do NOT put a 3" bichir with a 15" gar. although gars are generally peaceful predators, they can be somewhat unpredictable and will sometimes even take on food that they cannot swallow. a 3" bichir is far too easy a target for a hungry gar. if the bichirs and gars are of similar size they should get along relatively well (watch for frayed fins if the gar rest on the bottom near aggressive bichirs, i have noticed this with gars living with P.e.endlicheri and P.b.bichir).
there are always exceptions to the rule, but i wouldn't risk it with the small bichir unless you are willing to potentially sacrifice him as a feeder.--
--solomon
do NOT put a 3" bichir with a 15" gar. although gars are generally peaceful predators, they can be somewhat unpredictable and will sometimes even take on food that they cannot swallow. a 3" bichir is far too easy a target for a hungry gar. if the bichirs and gars are of similar size they should get along relatively well (watch for frayed fins if the gar rest on the bottom near aggressive bichirs, i have noticed this with gars living with P.e.endlicheri and P.b.bichir).
there are always exceptions to the rule, but i wouldn't risk it with the small bichir unless you are willing to potentially sacrifice him as a feeder.--
--solomon