Fossils, embryos and other clues provide evidence that fish evolved before birds. The evolutionary record indicates that limbs and wings developed over millions of years after fish evolved.
Approximately 400 million years ago, evidence indicates that lobe fish first came in to existence. Lobe fish are fish whose fins are bonier and contain more muscle than that of other fish, a precursor to limbs. Limbs evolved over tens of millions of years into creatures that were fully able to walk on land.
Feathers first appear in the known fossilized record about 150 million years ago and are currently thought to have evolved from the scales of reptiles.