Sounds like maybe it would not be such a good thing to have too many non native fish released in an area where they don’t belong. They might die anyway if conditions aren’t right or they could drive out the native species.
Primary example of that is the Asian snakehead in the Delmarva region. Someone released a few juvenile and a couple adult snakeheads into a pond in Crofton, MD, several years back. Snakeheads have labyrinth organs, which allow them to breathe air. They’re also apex predators who can pull themselves across land for considerable distances on their pectoral fins from one body of water to another, as long as it’s moist. At least a couple made it into the Potomac River before the state DNR netted the rest out, and now they’re infesting a 120 mile stretch of the river. On the upside, I hear they make a damned good batter-fried fillet.