i would definitely recommend you to try river prawns and fishes. for example, tom yum kung (spicy river prawn soup) and tom som pla kang (ต้มส้มปลาคัง).
even though, this restuarant is not beside the Khong river, we can enjoy the view and decorations. it runs by a nice couple, no other staff, so that it may take time waiting for your meals. please be prepared make an order before you visit.