I think you mean firebelly newt.
As for the best foods I use the frozen foods from Hakari (brand name, just like San Fransico Bay Company), live diced worms, white worms, black worms, and fruit flies for my terrestrials.
I've found my Chinese firebelly newts really love the frozen blood worms, mysis shrimp and live earth worms (and fruit flies for the terrestrials).
Hope this helps.
Rob