The sea trout is a migratory fish and it looks almost like the brown trout. Although the sea trout spends most of its time in the sea it hatches from eggs that have been deposited in fresh water. The hatching period lasts from one to three months depending on food supply and water temperature. The hatchling is also referred to as the alvelin and it is attached to a yolk sac, which is stored with food that can last for about a month. When the sac is empty the fish enters another stage of its life, the fry stage when it has to search for food by itself. After a while it starts to gain in color and it acquires camouflage looking almost indistinguishable from the brown trout. After a few years its color starts to become more silvery and the entire organism suffers changes so that it can cope w