Why does the fishball turned dark blue although fishball do not contained starch?

The dark blue color of the fishball could be due to a reaction with certain proteins or additives present in the fishball, potentially interacting with iodine or other reagents. It's also possible that the fishball contains ingredients like seaweed or specific spices that can cause a color change. Additionally, if the fishball was exposed to high heat or certain chemicals, this could lead to a change in color without the presence of starch.