Hatch
Also called Insect hatch, Bug hatch
A hatch is a period when aquatic insects emerge in numbers, often bringing trout into a steady feeding rhythm.
- Group
- Life stages
- Category
- Entomology & forage
- Level
- Beginner
- Water
- Freshwater
Last updated
What Hatch means
Hatch refers to a concentrated emergence of aquatic insects, usually mayflies, caddisflies, midges, or stoneflies. The trigger might be water temperature, light, weather, or time of day, and a single day's emergence can last minutes or stretch across hours.
Anglers also use “hatch” as shorthand for the whole sequence around emergence, nymphs rising, emergers in the film, winged adults, and sometimes the later spinner fall.
Why it matters on the water
Recognizing a hatch helps narrow the menu. Instead of cycling through random patterns, you can choose a fly type that matches the stage fish are taking, nymph, emerger, or dry fly, and then refine size and color.
It also changes where and how you look for fish. During a hatch, trout often set up in predictable lanes and feed with a repeatable cadence, which makes timing, drift control, and fly choice more important than covering water fast.
Read next
- CaddisflyA caddisfly is a common freshwater insect that trout and other fish eat in its larva, pupa, and adult stages. Many species live in streams and rivers, and their hatches can drive steady feeding.
- DunA dun is the newly emerged, winged subimago stage of a mayfly, right after it leaves the water and before it becomes a spinner.
- MayflyA mayfly is a freshwater insect with aquatic nymph stages that trout and other fish eat in every stage of its life cycle, from nymph to dun to spinner.
- MidgeA midge is a small two-winged fly; in fly fishing it often means a chironomid. Most of their larvae and pupae live in water. Midges hatch in every month on many rivers and lakes, and trout eat them year-round.