Bird is to Fly as Fish is to Swim

In this analogy, we need to explore the relationship between the two words provided in the first pair. The first pair is Bird and Fly.

Birds are known for their ability to fly. Now, look at the second pair of words provided: Fish and ___. Your task is to find the word that connects with 'Fish' in a similar way to how 'Fly' connects with 'Bird.'