Final answer:
Matisse's painting technique in Goldfish is characterized by vibrant contrasting colors and flatness, indicative of Fauvist style, which makes the correct answer option 1.
Step-by-step explanation:
The characteristics of Henri Matisse's painting technique in Goldfish reflect the style of Fauvism, characterized by vibrant, contrasting colors and a tendency towards flatness in the composition. Matisse's emphasis on expressive color over realistic depiction engages the viewer's senses and expresses emotions rather than capturing the natural world's fleeting effects, which was the concern of Impressionism.
Particularly in Goldfish, Matisse's bold use of color and flattened forms demonstrate the artistic innovations of Fauvism, focusing on the emotional power of his works. Therefore, the correct option that characterizes Matisse's painting technique in Goldfish is 1) Vibrant contrasting colors and flatness of the painting.