Inside this sunken ship, a mermaid peers through a round porthole, her long hair flowing in the current. Below her, a massive treasure chest sits open, overflowing with coins, jewels, and a delicate necklace. A friendly octopus clings to the side of a barrel, while a heavy iron anchor rests nearby among tangled ropes.

The wooden structure of the ship is detailed with wooden planks and tiny barnacles clinging to the surface. Colorful fish swim through the scene, darting between swaying seaweed and intricate coral formations. Every corner of this underwater world is filled with tiny details, from the texture of the old wood to the sparkling gems scattered on the ocean floor. You can see how the marine life has made this old wreck its home over many years.

Use bright, shimmering yellows and oranges for the gold coins and jewels to make them stand out against the darker tones of the shipwreck. The mermaid's tail can be colored with iridescent shades like teal, purple, or seafoam green to give her a magical appearance. For the octopus and coral, try using bold pinks or oranges to add pops of color throughout the scene.

To create depth, use darker browns and grays for the wooden planks and barrels, while keeping the water in the background a lighter, translucent blue. Colored pencils work exceptionally well for the smaller details like the necklace and barnacles, allowing you to stay within the lines while adding fine layers of color. Adding a touch of white gel pen to the jewels can create a sparkling highlight effect.