Fishbone stitch in two colours

 Two different colour threads are taken intwo needles and fishbone stitch is worked alternately with the two colors.

A centre straight stitch and the two left and right stitches are fine in first color ,then needle with second color is taken and the next set of left and right stitches are done in second color.

Inthis way whole shape is filled

https://youtu.be/W9AHS6N1F0U this is the video tutorial on YouTube for the same.