Yes but they are bony and the flesh is too firm just as their cousins the White Tilapia is bony and too soft. There are better tasting freshwater fish than these. But, they are relatively cheap and a source of protein.
As another member has said, every individual in the nation would have to consume several daily to make a dent in the numbers.
The Government are toying with a plan to release so called Sea Bass (Barramundi?) Into waterways to eat up the Blackchin. Better tasting but is it the right solution?
Mass capture for conversion into fertlliser is another option but.......🙄