Amphioctopus fangsiao (d’Orbigny, 1839–1841), aka Octopus ocellatus (Gray, 1849), is widely distributed in coastal areas of West Pacific Ocean. A. fangsiao has high market value because of the delicate meat texture and enriched nutrition. Hence it has been one of the most important economic species in the north coast of China, and the development of the culture industry is promising. In this study we used new hatchlings to study the food requirement of A. fangsiao at different developmental stages. We first observed the feeding behavior under different conditions, and then investigated the growth process of A. fangsiao fed on different diets at different developmental stages. As the density of Artemia nauplii (the food) increased from 0.1 ind./ml to 1 ind./ml, the highest food intake rate of the hatchlings occurred when the density was 0.1 ind./ml. Because the feeding behavior of hatchlings aged Day 1–2 and Day 2–3 was highly active, the diet should be carefully prepared starting from Day 2 after hatching. The food intake of new hatchlings was usually active in the nighttime, and was especially intense in the shimmer and dark environment. A mixed diet helped improve the growth and lower the mortality rate. Artemia nauplii was the key diet at the para-larvae stage (0.03 g). A switch of diet was needed at the benthic stage (0.1 g), and shrimp and fresh shellfish meat was the optimal combination for the benthic hatchlings. Results of this study may provide important information for the large-scale culture of A. fangsiao.