Ok…did some research on Chinese dragons and perhaps the tail is holding a flaming pearl. Here's some good info.
Some scholars report that the Huang Di (Yellow Emperor) used a snake for his coat of arms. Every time he conquered another tribe, he incorporated his defeated enemy's emblem into his own. Huang Di was immortalized into a dragon that looks like his emblem. That explains why the Chinese dragon has a body of a snake; the scales and tail of a fish; the antlers of a deer; the face of a qilin (a deer-like mythical creature with fire all over its body); and two pairs of talons of eagles; and the eyes of a demon. They fly in the sky among the clouds. Almost all pictures of Chinese dragons show them playing with a flaming pearl. Supposedly it is the pearl that gives them their power and allows them to ascend to heaven. Chinese dragons are occasionally depicted with bat-like wings grown out of the front limbs, but most do not have wings.
Also, since the Chinese consider Huang Di as their ancestor, they sometimes refer to themselves as “the descendants of the dragons”.