I learned a new technique, one that silk artist Daniel Jean-Baptiste uses a lot. That is how to paint water with light reflecting in it. The technique is really simple. It's a wet in wet technique, but any shapes in the painting like the fish, need to be outlined first with some type of resist so the paints/dyes don't flow into areas where they don't belong. Wet the entire area with plain water, using a regular brush " dot" areas of color on the wet surface, then let them alone and just let them bleed as they will. This produces lighter areas of color that bleed from the original color dot. Some areas around the area will remain white, giving the illusion of light reflecting in the water. Water and light have always been some of the toughest effects to produce, this technique makes it easy. Daniel Jean-Baptiste has many wonderful videos on YouTube showing this effect. And he also has a website. This method is used on silk habotai but it might work on other grounds like watercolor paper or canvas, you would have to feather out the edges to blend instead of leaving a hard edge. This is one of the beauties of silk painting, it bleeds so the edges feather & blend on their own due to the nature of the silk.