I have never kept a Pbass before but would like to introduce one or two into a tank with my Dorado. The Dorado is 15" and aggressive. He has never killed another fish but he will bully whoever he can. He is currently in a tank by himself. My questions are: Is this a viable option? How large should the Pbass be pefore I introduce them to the Dorado? What type of Pbass do you recommend?