The San Juan below Navajo Dam isn't one uniform fishery — it's zone-led, rule-led, and flow-led, and the single most important thing to get right is which set of rules you're standing in. The famous water is the Quality Water immediately below the dam: special-regulation trout water, catch-and-release, artificial fly or lure on a single barbless hook, and a hard limit of only two flies per line. Downstream of that the rules ease, the species mix widens to catfish and striped bass, and harvest opens up — so don't let the Quality Water reputation bleed into the lower river. It's a controlled tailwater too: the Bureau of Reclamation sets the release at Navajo Dam, and a change can move depth, current speed, and your safe wading lines overnight. The San Juan is genuinely beginner-friendly for catching numbers, but it's technical to do well — depth and drift control matter far more than which size-24 you tie on. Always check current New Mexico Game and Fish regulations, the current Navajo release, and the exact reach you plan to fish.