Serving the fish in traditional batter to 100 consumers, they found that 39% preferred the pangasius while 16% preferred carp and 43% said they preferred the traditional cod. Big headed carp is a silver coloured species of carp that can grow up to 100lbs in size and is found in lakes of eastern Asia. It has a pink flesh and the researchers believe it could be used to replace trout or salmon. Silver carp is commonly cultivated in China while pangasius is a type of catfish found in the Mekong river in south east Asia. Both have a mild white-coloured flesh and could be a good alternative to cod,.