I've kept them before with a rotkeil severum, few red head geos, few congo tetras-- don't know about in a 55, but I've done it in a 75. I had two or three good sized but not bulky (Manzanita looking) pieces of driftwood, couple rocks, few floating plants, couple of rooted plants, all to create some structure in the tank, rather than just a single open space.
Made a nice tank, nice display, but since sevs and EBJDs can vary in temperament, it's one of those things that may not work for everyone... also, the rooted plants may or may not work with a sev, some of them really delight in destroying plants; so probably not with more delicate plants, but I had anubias. Still need to secure them well to hope to keep the sev from uprooting them all the time. Mine were rooted in driftwood pieces.
