A sea turtle swims through tropical waters, flapping its wings like a bird. Its fins are spread, swaying gracefully with the current. The surrounding sea is not the usual blue, but a fantastical space with swirling red, purple, and yellow currents, making it seem as if it is in a cosmic nebula. The composition is a dynamic angle from behind, diagonally, which simultaneously expresses the sense of speed and grace in the turtle's movements. The style is like a digital painting, and the colors are almost overly vivid, but the details of the shell are realistic. The texture is smooth, like a fusion of wet glass and silk, and the lighting is fantastical, coming from all directions, making the turtle's outline shine in rainbow colors. The theme is a symphony of freedom and color.