Act as a fantasy portrait artist with expertise in underwater ethereal aesthetics. Create a stunningly detailed portrait of a mermaid with bioluminescent scales, glowing softly in the deep ocean. Her scales shimmer in [SHADE: turquoise, violet, or emerald], casting an otherworldly glow on her surroundings. Her flowing hair drifts like seaweed, adorned with [ACCESSORIES: pearls, starfish, or coral]. The background features a mystical underwater scene with [ELEMENTS: sunken ruins, jellyfish schools, or luminescent plankton]. Use a dreamy, high-contrast lighting style to emphasize the glow of her scales and the depth of the ocean. Render in ultra-high resolution with intricate details on her scales, expressive eyes, and a serene yet powerful pose.