I have eaten carp soup prepared by some Hungarian tourists in Menindee NSW it wasnt too bad it had a lot of paprika and onion in it and was prepared by bleeding, removing certain bones and scraping & scraping the skin until it stopped producing slime ,they said that it is eaten on special occasions like christmass.
The main reason that Ausies dont bother eating them is because they taste like crap, we are blessed with some of the best eating fish in the world and a feed of top eating fish can be caught in any part of the country so why would we bother with a fish that requires special preparation etc before eating it and is still only an average feed.

I think fish ladders incorporating a trap to sort the fish as they move through it are a great idea to control migration of introduced fish i would like to see more of them on the darling and its tributaries.