ABK are way nippier. And more food aggressive. You can keep those two together, the signals won't cross. Just have a big tank because BGK command a large space at night when they're most active. A 75 gallon should suffice.
It may just be my one ABK. He is so nippy. He doesn't even try to kill the other fish, just nip. I thought that the other didn't do it because they were less dominant, but it may be that the dominant one is an oddball.I wouldn't say that ABK's are nippy but they're definitely extremely curious. When I had mine, it would always swim straight up to new fish then just swim away. As far as their electrical currents causing death, I think it depends on how big the tank is. I kept an ABK with an aba aba knife for 6 months without problems until I felt the aba was big enough to move into the big tank.
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