Beside the Fish
There is breath in the water.
Water holds more than meets the eye.
Fish rely on oxygen dissolved in water. This is oxygen gas within the water, not the oxygen bound inside water molecules.
Temperature matters: cooler water can hold more dissolved oxygen than warmer water. Movement, photosynthesis and the breakdown of organic matter also affect oxygen conditions.
Follow oxygen toward the life of a waterway, or follow a different kind of breath into Heart.
Evidence beneath this connection ↓
THE CONNECTION
Fish and people both depend on oxygen, but obtain it in different ways. The comparison opens a Track; it does not make gills and lungs interchangeable.