Marie River: The peacock bass is an aggressive predator that attacks extremely fast. Use baitfish flies in bright, vivid colors like green, yellow, orange, and black. Ideal size is 10-15 cm, tied on quality barbless hooks (1/0 to 4/0). Foam poppers, Nyap, and large mice patterns also work well, as do divers. If you often fish in saltwater, bring your streamers and poppers as they work great for peacock bass too. While flies are available at the lodge, it's still recommended to bring a good selection.
Pirarucu: Arapaima usually attack the fly deep underwater, using their senses to locate it. Therefore, the best patterns are large baitfish flies between 15-25 cm in length that displace a lot of water when stripped. Since we're targeting a very strong fish, only use the best hooks in sizes 4/0 to 8/0, such as Tiemco SP 600, Owner Aki, or Gamakatsu SL 12 S.
As we're using full sink lines, there's no need to add extra weight to the flies. Baitfish flies with wiggle tails are also a good choice. The best colors are a topic of debate, but I believe it doesn't matter much as Arapaima don't hunt by sight.
Aside from Arapaima, it's also enjoyable to catch a few Arowana in between. The best flies are small surface foam poppers or small baitfish flies in the 7-12 cm range.
For Tambaqui, a round fish similar to Pacu, fruit fly patterns tied on strong hooks are suitable.