A salmon begins its life as a fertilized egg, laid in gravel at the bottom of a river. As the salmon grows inside the egg, it develops eyes, a spine and a tail. After hatching, the salmon is known as an alevin. They receive nutrients from a yolk sac attached to their body.

Alevin hide from predators in the gravel at the bottom of rivers. Fry look like tiny fish. They begin to swim around in search of food. Most salmon fry have vertical stripes on their bodies called parr marks, which help camouflage them from predators.