The trout spawn is the most important event in a trout's year, and understanding it is the key to catching fish before and after. Trout don't feed while they're actively spawning — they're too busy building redds, defending territory, and reproducing. But the periods before and after the spawn are when trout feed most aggressively, and those are the windows when the biggest fish are the most catchable. This guide covers the three phases of the trout spawn and how to fish each one.
The pre-spawn is the feeding binge. As water temperatures approach the spawning range, trout start eating heavily to build energy reserves for the reproductive season. For fall spawners (brown and brook trout), the pre-spawn happens as the water cools into the low fifties. For spring spawners (rainbow and cutthroat trout), the pre-spawn happens as the water warms into the mid-forties to low fifties. During the pre-spawn, trout move from their deep-water holding lies toward the spawning areas — shallow, gravel-bottomed riffles and runs with good flow. They're feeding aggressively, they're moving, and they're catchable. Fish the transition water — the pools and runs between the deep holding lies and the shallow spawning flats — with a bigger bait and an active retrieve. The pre-spawn is when you catch your biggest fish of the year.
The spawn itself is the time to leave the fish alone. When trout are on redds — the gravel nests they dig in shallow riffles — they're not feeding. They're defending territory and reproducing. Fishing for spawning trout on redds is unethical and harmful to the fishery. The fish are stressed, they're vulnerable, and disturbing them can destroy the next generation of fish. Learn to recognize a redd: a clean, bright patch of gravel in a shallow riffle, often with a pair of trout holding over it. When you see spawning activity, move to different water. There are plenty of fish that aren't spawning that will eat — target those instead.
The post-spawn is the recovery feed. After the spawn, trout are exhausted and hungry. They move off the spawning areas and back to their holding water — deeper pools, runs, and lies where they can rest and feed. For fall spawners, the post-spawn happens as the water gets cold after the spawn. For spring spawners, it happens as the water warms after the spawn. Post-spawn trout are not as aggressive as pre-spawn trout — they're tired and they're recovering — but they're eating to rebuild energy. Fish a smaller bait, fish it slow, and fish it in the deeper water near the spawning areas. The fish are there, they're eating, but they won't chase far. Put the bait in front of them and let them eat it.
Water temperature is the trigger for every phase of the spawn. Brown and brook trout spawn when the water hits 44 to 48 degrees in the fall. Rainbow and cutthroat trout spawn when the water hits 42 to 48 degrees in the spring. A stream thermometer is the most important tool for understanding where the fish are in the spawn cycle. If the water is in the pre-spawn range, fish aggressively in the transition water. If it's in the spawning range, leave the redds alone and fish the water nearby. If it's in the post-spawn range, fish slow and deep in the recovery water.
The spawn cycle also affects where fish are located in the river system. Pre-spawn fish are moving from deep water toward spawning areas — fish the runs and pools between the two. Spawning fish are on the redds in shallow riffles — don't fish for them. Post-spawn fish have moved back to deeper holding water — fish the pools and runs below the spawning areas. Understanding this movement pattern tells you where to look for fish at any point in the spawn cycle. The fish are always somewhere — you just need to know which phase they're in to know where to find them.
Tiger trout and Arctic grayling don't reproduce naturally in most waters — tigers are sterile, and grayling have their own separate spawn cycle. But they still respond to the same water temperature changes and the same feeding patterns. A tiger trout will feed aggressively in the same pre-spawn window as the browns and brooks in its water, even though it's not spawning itself. The spawn cycle drives the entire food web — the baitfish that trout eat are also affected by water temperature and seasonal changes — so even non-spawning species follow the same patterns. Understand the spawn, understand the water temperature, and you'll understand when and where the fish are feeding, no matter what species you're after.