My adults are more like 4 inches, so these may be juveniles. Are they fully aquatic? Where did you get them? Here's a good caresheet, though I see nothing about frequency of feeding.
Caudata Culture Species Entry - Cynops orientalis - Chinese firebelly
I feed my adults 2-3 times / week, as much as they can eat in a few minutes. I feed mine a variety of live and frozen/thawed foods. The problem with frozen and thawed bloodworms is that they can foul the water quickly, so you don't want to overfeed them. Live blackworms live in the water and won't mess up the water.
I feed my aquatic juveniles almost daily. Other, more experienced, hobbyists may have better suggestions, but this is what has worked for me. My terrestrial juveniles
also eat almost daily. My believe my original pair had been wild caught. They did not eat for weeks and wouldn't go in the water for weeks after purchasing them. It is a sign of stress.
My female laid eggs on plants, live and plastic. She would grasp the plant and deposit the eggs, one at a time.
Good luck,
Dana