[Guangming Museum Drawing] There are some tips for “drawing fish”: taking the coral reef fish of the South China Sea as an example

The South China Sea is the most biologically rich sea area in my country. It is a tropical and subtropical sea area located south of the Tropic of Cancer, with an area of ​​about 3.5 million square kilometers, which is about three times the total area of ​​Bohai Sea, Yellow Sea and East China Sea. Although coral reefs only account for 0.2% of the ocean area, they are home to one-third of the marine fish species, about 5,000 species. In the long process of symbiotic evolution with corals, coral reef fish have evolved colorful appearances and unique survival characteristics such as feeding, avoiding enemies, living, and reproduction.

The fish of the order Sibiriformes are very representative fish. The genus of the genus Sibiriformes is also commonly known as the trigger fish. Most of them live in shallow waters in tropical seas, living on corals and large-leaf seaweed. They are used to lying freely at ordinary times, but when they encounter danger, they will quickly drill into the coral reef hole, erect their dorsal fins and fix themselves tightly in the hole. The trigger fish not only plays an important role in the ecosystem, but also has great aesthetic value in terms of viewing.

Many times, nature wants us to find differences. There are subtle differences hidden quietly between two very similar creatures. If we simply describe them with words, we may not be able to accurately identify the differences between the two. At this time, natural history drawings can become an efficient means of visualization.

Figure 1. Black-banded triggerfish hinecanthus rectangulus (triangular cannonball)

What is the importance of natural history drawings for biological classification?

For very similar species, judging their differences in traits and clarifying effective classification features are important bases for species identification in animal books or biological illustrations. Generally speaking, an excellent illustration contains two parts, namely text description and drawings. If there are only words, it will be difficult for people to imagine and verify; if there are only drawings, people will have preconceived ideas and ignore details. Therefore, the two forms complement each other to achieve better results.

What should we pay attention to when painting?

If you start drawing blindly, you will constantly have questions about the morphology, structure, and color. How should I draw this? What is the shape? How many fins should I draw? Therefore, before drawing, you must have a basic understanding of the morphology of the species you want to depict. It is not just about referring to text or existing illustrations. If necessary, you also need to measure the data of the real object and make sufficient reference.

First, start with the view: different views are used for species of different forms. When learning to draw, multiple views as references are essential to the design. Its significance lies in expressing the volume and image of the object itself. In popular science drawings of fish, the whole fish is usually composed of the side, back and ventral surfaces. There are four basic body shapes of fish: spindle-shaped, laterally flattened, flat-flat and stick-shaped. Spindle-shaped and laterally flattened are mostly in side view; flat-flattened are dorsal and ventral views; flat-flattened are also mostly in side view. For figures that are difficult to see on a flat surface, you can add a cross-sectional view based on the side view.

If some parts change too much, you can also further understand the morphology through multiple cross-sections. There may be different morphological differences from the head to the tail. It may be difficult to judge its true morphology only from the side, back, and ventral images. At this time, if there is a cross-sectional diagram, it will be better to understand it. Even if the body shape is the same, the body width or height is also the main basis for identifying species, so when drawing, the proportions of various parts of the body must be determined first, and then the morphology of each key part, and the schematic diagrams that adapt to different states are also very important. For example, the shape of the eyes, the size of the mouth, the shape and number of fins and scales.

Figure 2. Brown triggerfish Balistoides viridescens (Titan Cannonball)

When drawing, the differences between species should be emphasized, and the differences between individuals of the same species should be reduced. In addition, the same species and different sexes may also differ at different developmental stages, which greatly interferes with the identification of the species. In order to avoid cognitive bias and better understand the species, it is sometimes necessary to draw schematic diagrams of the different developmental stages of the species and gender differences. Some species will have large changes when opening their mouths or unfolding some body parts. These changes may contain traits that are very important for species identification, and images of different states sometimes need to be drawn.

Fish often have many unique patterns and colors on their bodies. When painting with a linear technique, use dots of different densities to represent the material and color. Generally speaking, the denser the dots, the darker or rougher the surface color, while the sparser the dots, the smoother and lighter the surface color. When painting, the original saturation is often increased to ensure that the drawing record of the species is not interfered with by ambient light or other factors.

Following the above rules, this time four closely related species of the family Pufferfish are depicted and displayed. It can be seen that they have similar body shapes and first dorsal fins, but the body patterns, tail shapes and tooth characteristics are very different. Through natural history paintings, we can clearly see these characteristics and differences, so as to accurately identify the species. In addition, we can also use software to combine and design scenes.

The vast South China Sea is home to countless fish species and is also the cradle of natural history paintings. We look forward to more exquisite natural history paintings being created here, drawing a blueprint for the protection of coral reef fish diversity in my country.

Figure 3. Redtooth triggerfish Odonus niger (Devil's Cannonball)

Figure 4. Balistoides conspicillum (Clown triggerfish)

Figure 5. Scenario summary design

Author: Mao Yufan (School of Design, Jiangnan University)

Scientific review: Zhang Jie (Associate Researcher, Institute of Zoology, Chinese Academy of Sciences)

Co-ordinator: Zhao Qingjian