They are ambush predators, so they can't be expected to be swimming around like zebra danios all the time. They will indeed be quiet, but the speed of a strike when food presents itself is startling. If you are into predator fish, these guys fit the bill in spades.
I kept them for several years back in Ontario, where I was able to collect them from local waters that were often in the high 70's F during the height of summer. They did well in my room-temperature tanks. I spent a couple years trying to breed them, but the only interactions I ever saw ended with the tail end of one fish hanging out of the mouth of the other...sometimes with both fish dead!
In hindsight, I wonder if they were like the Gymnogeophagus cichlids and other aquarium fish from southern South America, which apparently don't breed well or live long if kept warm all year long? My fish came from a climate that saw them living under ice for several months each year, so room temps year-round were not a very natural situation for them.
Another thing to bear in mind is that bichirs are slower, more bottom-oriented feeders. Pike are get-your-fingers-out-of-the-way maniacs. Getting any food to your bichirs would be challenging with this mix of species in the same tank. Feeding will not be a simple case of shake a can over the tank and sit back and relax; it will be much closer to a tactical military operation.
