most Aequidens spp. are pretty mild for cichlids. should get along fine w/ your bichir and should last a long time, if not for life, in a 55g. Of course, as other have said, some can be aggressive.
I don't have any experience w/ true green terrors, but you're probably talking about gold saums anyway
I don't have any experience w/ true green terrors, but you're probably talking about gold saums anyway