If you had knowledge of a little more scripture, you'd realize the answers to your questions.
The reason Noah didn't need to take 2 of every fish is they weren't going to drowned.
Airborne creatures died. They has no place to rest. And no food.
Here is the list of what died:
Genesis 6:7 20-23 And all flesh died that moved on the earth, birds, livestock, beasts, all swarming creatures that swarm on the earth, and all mankind. Everything on the dry land in whose nostrils was the breath of life died. He blotted out every living thing that was on the face of the ground, man and animals and creeping things and birds of the heavens.”
The reference to “dry land” limits what types of life was affected. The fleshy breathers on the face of the earth.