This might not sound like an answer, but the key to painting water is understanding water. So there's a few things going on in my water above. The first is the reflections, the second is the scattering of light beneath the water on the right and the third is the sub-surface scattering of the light on the left.
Color (light) in water tends to be darker and more saturated. Also, objects beneath the water tends to reflect the color of particles within the water itself. You can see this in blue-green oceans, muddy water, etc. Water also becomes more reflective as it moves away from you so water that's further away will reflect like a mirror.
There's a lot going on with water which is why it's also difficult to paint.
It helps a lot! Thank you! There's so much I don't understand with water yet then, I will keep studying it. I will keep your answer in my messages too, to read it a few more times! Thank you again, so much, I will keep practicing and studying!