It is a Chinese Fire Belly.
I used to feed it frozen blood worm and dried daphia. Ever since that it started to become very secretive and fled away when I hand feed it, I think it has rarely eat for two months already.
During the two months, I have introduced feeding chopped live earthworm, it accepted the first meal. But refused since then. So I relocated it to a small tank. Then tried live Cricket as well. But still no good.
It stayed in water all the time. it still move around pretty well and active. Just not taking food. I noticed that it skin became rougher and the white markings became much more visible like the other bigger adults I have. The skin became shiny also.