This is good, but I think the colours are garish and those tiny, tiny hooves in the last frame are alternately hilarious and spooky.
I think the problem with the colours is too many full, bold, deep colours. Clashes. Take a close look at the actual show ponies - they're really pale shades of blue, purple, orange, green etc on their coats. The manes tend to have fuller colours. Tone down the purple and you'll get a gentler transition.