Hello
That is a very pretty Northern Blue Tongue Skink(BTS). Very red colors. But to answer you questions:
Fish - Blue Tongue Skinks rarely eat fish in the wild. In captivity most reputable breeders stay away from fish. Many fish have parasites that are transmittable to Blue Tongue Skinks. It is not recommended to feed them.
Pinky Mice - Replace with Rat pups(Pink rats are healthier). Can be fed on occasion and to thin skinks.
Cricket - Sometimes carry pinworms. They bite on the skink's feet. The have little nutritional value. Skinks often ignore them. They are usually only fed to skinks that are over weight and need to chase something.
Mealworm - Not bad, but not good. Best to be replaced with Superworms, Goliath Horn Worms, Silkworms, roaches, snails, and night crawlers.
Wet Cat Food - Most breeders feed a diet of almost exclusively cat/dog food with greens mixed in. This is recommended.
Was the breeder's name Jeff?