The most effective way to protect wild life resources and to meet the market’s demand is artificial aquaculture. The low survival rate of sea horse juvenile due to low food intake slowed down the development of the culture industry; however, the reasons that impact feeding behavior and its metabolism of the juvenile are unclear. To address this, ten 2- or 3-day-old juveniles of Hippocampus kuda were fixed in paraformaldehyde with PBS, and its skeletal morphology of the snout tube was observed and analyzed. The tube snout’s profile and structure included metapterygoid, quadrate and symplectic, were important to juvenile’s feeding. A hole composed of metapterygoid and the end of symplectic is the smallest diameter in the snout tube, which decided the size of the feeding food. In addition, there is a crevice between metapterygoid and symplectic, which could slightly compensate the limitation in the snout tube and can pass bigger food than the smallest diameter. These observations suggest that properly increasing the size of food might enhance feeding efficiency and promote survival rate.