Just because they're banned doesn't mean they're always destroyed. And there is a distinction between possession being banned due to being an invasive, or destructive unwanted organism and banned because they're endangered.I've always wondered what would happen if a guy got his hands on a couple pairs of banned fish that were only banned because they were endangered in the wild but then he found a way to breed them and started doing it on a large scale. Would he be a special circumstance thus be granted exemption from the law? Would the law be as cold as ever and seize his animals and have them destroyed?
You're caught in illegal possession of a breeding population of dozens of koi? Yeah, they're banned for being destructive, they'll kill them all. You have an illegal breeding population of dozens of kakapo, you really think they'll kill them? No.