It's a bit expensive and over the top, but San Silvestre, on the main road next to Las Palmas, remains unchallenged as the best restaurant in town. The surubí al coco (a local catfish in coconut sauce) is a real standout, though the gargantuan pique macho (beef, sausage and chips) is great if you want to pig out.
Restaurant San Silvestre
Amazon Basin