For this coloring page, I would suggest bringing out the cartoon mermaid's vibrant personality with a color scheme that replicates her cheerful facial expression. I would start by adding a bright pink color to her tail and a rich purple to her bikini top. Then add turquoise blue to her lush locks, which will be offset well with delicate yellow highlights. To bring the vivid colors to life, add delicate shading of blues and purples to her skin and tail. For the water tiles, I think a cool aqua blue makes them seem more like a pool, and adding a teal green for the plants will make them stand out. To bring her lively pose to life, try adding different shades of yellow, pinks, and purple to the arms and hands. With these colors, this beautiful mermaid will certainly be brought to life.