How do fish breathe underwater?

1. 1

   Wobble says

   Water has oxygen mixed into it. That's the part of air that living things need to breathe. A fish gulps water in through its mouth and pushes it out over its gills. As the water flows past, the gills take the oxygen out of it.

   For ages 4–7
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   Checked against Blue in the face: breathing underwater (U.S. National Park Service)

2. 2

   How do gills take the oxygen out?

   Each gill is made of tiny threads called filaments, and every thread is full of little blood tubes. As water flows over the threads, oxygen slips out of the water and into the blood. Then the blood carries it all around the fish's body.

   For ages 6–9
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   Checked against How do fish breathe? (Ask Dr. Universe, Washington State University)

In Lil' Phil, reaching the bottom of this wonder earns a sticker for Wobble's collection.

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