I have 2 adult females, and 1 teenage male in a 65 gal tank with 4 salvinis and 5 giant danios. Aggression in the tank between the pikes (actually all of the fish) is pretty much nil. The biggest female pike rules the tank. She will flare at the others and the salvinis if they're in her way, but otherwise no violence. The tank is sparsely planted, but there are several large pieces of driftwood that provide hiding places.
I love my BCs. They are honestly more personable and active than my juvenile Johannas.
I have mine in the 45gal community, used to be in the 55 with the FH till I added the RBS & Texas. It held its own against the FH, seen it liplock & slam the bigger FH. I like the personality & it will eat alot of rosys.