Even native fish should never be returned to the wild once they are captively kept. Even if your certain they were caught from the same catchment. It's not just the disease/parasite risk, it's unknown genetic and behavioural influences too.
Unfortunately I see a lot of accidental fish releases that were easily preventable. Well intentioned but poorly planned aquaculture endeavours. Private dams getting stocked.
In Australia, the government deliberately introduce native species from one area into new areas for sports fishing with devastating results to the original ecosystem. Fishermen, tourism and park managers are happy though.