I am starting to take care of a partially stocked 90 gallon tank. Current inhabitants are a common pleco (8 inches), six zebra danios, two cory cats, and about ten swordtails. I want to bulk out the cory cat school and am also hoping to get something that will keep the swordtail population in check. Any suggestions for something that will eat lots of swordtail babies, but isn't so aggressive that it will bully my other fish? I would like a centerpiece fish. Some sort of cichlid would be great!