I say ideally an all male tank as convicts will try and breed with anything. 3 or 4 male cons, a green terror is a good suggestion as they cant breed with cons if it happens to be a female, and maybe a nic. male or female they do not crossbreed much either. sounds like a good stock to me. IMHO if you are not a fan of convicts dont get them, they can become more of a nuisance than entertaining. i only keep one male specimen at a time and only as an enforcer in my unruly grow out tanks when i cant get/afford a parrot large enough. the instant he starts breeding with females i fire him for sexual harassment on the job...lol. parrot males do a far superior job. less damage inflicting, sterile, easier to rehome and people find them interesting...i dont really