Underwater Reef Coloring Page

Stable Diffusion

By Varun Sharma Tested with Stable Diffusion SDXL 1.0 Jul 28, 2026

Underwater Reef Coloring Page is an SDXL 1.0 prompt for a printable reef scene at 3:4. Requiring every outline to be a closed shape is what stops digital fill and marker ink bleeding across the page.

Last tested: July 2026 with Stable Diffusion SDXL 1.0

Part of the Stable Diffusion prompt library · see more line art prompts .

Remix in builder

Coloring page outline of a reef with a sea turtle, clownfish, anemone and branching corals — Underwater Reef Coloring Page — Stable Diffusion SDXL 1.0, Aspect ratio 3:4

Commercial use included

Prompt

A coloring page line drawing of a coral reef scene, a sea turtle gliding across the centre of the frame, three clownfish among anemone tentacles with their body stripes drawn as outlined bands left completely unfilled rather than blocked in, branching staghorn coral and rounded brain coral along the seabed, a few kelp fronds rising at the left and right edges, drawn in clean uniform black outlines of even weight on pure white, every shape fully closed so colour cannot leak between them, no shading, no grey fill, no hatching, no solid black areas, generous open shapes, no text

Negative prompt

blurry, low quality, shading, grey fill, cross-hatching, solid black areas, photorealistic, colour, text, watermark, broken open outlines, dense tiny detail, thin faint lines, filled stripes on fish, black markings on animals

Settings

Model: Stable Diffusion SDXL 1.0
Aspect ratio: 3:4
Steps: 30
CFG scale: 6.5
Sampler: DPM++ 2M Karras

How to use this prompt

Closed shapes are the requirement nobody writes down and every reef page needs. Anemone tentacles and kelp fronds are exactly the forms SDXL leaves open-ended, and one unclosed outline lets a digital fill flood the entire page or a marker run out into the water. "Every shape fully closed so colour cannot leak" is the instruction that fixes it. The second control is density: reefs are intrinsically intricate, so naming three specific corals caps the detail where asking for "a reef" would bury the page in texture too fine for a child to colour.

Variations to try

Simplify for toddlers: one large turtle, two fish, three coral shapes, and much thicker lines
Swap the biome to a kelp forest with an otter, sea stars and rocky ledges in the same line style

line art whimsical coloring pages childrens book

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Whimsical Children's Book Prompts Whimsical Stable Diffusion Prompts Line Art Stable Diffusion Prompts Line Art Coloring Pages Prompts

What to do next

Adapt it →

Open this prompt in the Stable Diffusion builder, pre-filled, and change one layer at a time.

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For developers — copy this prompt as JSON

{
  "title": "Underwater Reef Coloring Page",
  "prompt": "A coloring page line drawing of a coral reef scene, a sea turtle gliding across the centre of the frame, three clownfish among anemone tentacles with their body stripes drawn as outlined bands left completely unfilled rather than blocked in, branching staghorn coral and rounded brain coral along the seabed, a few kelp fronds rising at the left and right edges, drawn in clean uniform black outlines of even weight on pure white, every shape fully closed so colour cannot leak between them, no shading, no grey fill, no hatching, no solid black areas, generous open shapes, no text",
  "negative_prompt": "blurry, low quality, shading, grey fill, cross-hatching, solid black areas, photorealistic, colour, text, watermark, broken open outlines, dense tiny detail, thin faint lines, filled stripes on fish, black markings on animals",
  "model": "Stable Diffusion",
  "model_version": "SDXL 1.0",
  "settings": {
    "aspect_ratio": "3:4",
    "steps": 30,
    "cfg": 6.5,
    "sampler": "DPM++ 2M Karras"
  },
  "style_tags": [
    "line-art",
    "whimsical"
  ],
  "use_case_tags": [
    "coloring-pages",
    "childrens-book"
  ],
  "source_url": "https://promptkoi.com/prompts/stable-diffusion/underwater-reef-coloring-page/"
}

The whole library is available as an open JSON dataset · developer docs.