They use a internal pouch which is named swim bladder.
Explanation; Oxygen will enter a fish’s mouth, and passes through their gills. The oxygen will be taken and gets carried by hemoglobin through their bloodstream. Hemoglobin will take out some of the oxygen into their swim bladder. The amount of oxygen will show if they will sink or rise. Your question is how do they rise. If he goes up too much, the meaning of this is when the gas diffuses into their blood and out the gills.
Got this from a writing, but rephrased it.
They are descended from wild plants.
Answer:
Aquatic ecosystems include oceans, lakes, rivers, streams, estuaries, and wetlands. Within these aquatic ecosystems are living things that depend on the water for survival, such as fish, plants, and microorganisms. These ecosystems are very fragile and can be easily disturbed by pollution.
Explanation:
