(Very old original song) Young Crucian Carps Hua & Jia_Theme

The melody of this song was created when I was in the first grade of primary school as the theme song for my story "Young Crucian Carps Hua & Jia". The story describes the daily life of 2 crucian carps "Hua Hua" and "Jia Jia", whose hobby is to study reinforced concrete.
I'm not sure if the melody has ever been influenced by another song, as it sounds very familiar.