Life Cycle of A Trout

Life cycle of Trout

The Trout’s Life

The Trout has a fairly simple life cycle. I will break it down to the various parts here and explain a little about each cycle.

The Eggs

These eggs are laid in a gravelly and fairly swift area of a stream. The brook and brown trout will spawn in the fall, while the rainbow and various cutthroat species will breed in the spring.

The Alevin

Alevin, or trout with a yolk sac still attached.
Image courtesy of Auburn University

This is a newly spawned salmon or trout still carrying the yolk sac. They derive nutrients from this yolk until they are large enough to begin eating normal food. The consumption of the yolk will usually take two to three weeks.


As soon as the yolk sac has been absorbed by the trout, the next life cycle is called “fry”. At this stage the fish will begin eating small insects and larvae. They look very similar to adult trout but have light coloration and non distinct spots. They are often difficult to determine the species when small.

Fingerlings (Juvenile Trout)

These are simply one step larger than fry. They are starting to get more defined coloration and are beginning to look more like the adults. Often called “fingerlings” because they are about the size of a small finger.


The adults are the mature broodstock or breeding stock. The mature fish we all want to catch. You can learn more about the breeding habits and process here.

The time frame or the full life cycle of trout can vary with the species and habitat and conditions.



Watch this Recent Troutster Video!

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