Bichers aren't really aggressive (actually territorial) like cichlids, but they are predatory fish regardless of size/age, and will eat any other fish if they'll fit into their mouth. I had an ornate bicher some years ago, kept it for a few months until it outgrew my 30 gallon tank. I picked up an adult pair of convicts, one of the nastiest species for their size, thinking the bicher would eat the hundreds of fry they would regularly produce. The bicher ate the female convict less than a week after they were placed in the tank, the larger male a few weeks later. The bicher was only around 6" long, and the convicts looked like they were too big for it to eat.