We are running short on conger eel, so we need to place an order for them soon.
Since it is difficult to get conger eel in America, freshwater eel is used instead.
"Do you want another piece of conger eel nigiri?" "Sure. Why not?"
A hole child isn't some kind of creepy hole child (not sure how else to describe it). It's a conger eel, a type of tasty eel eaten in Japan. It might be easier to learn the reading first, though, and use that, because the second meaning option is anago, the Japanese word for it (also used in English).
The reading is the two kun'yomi vocab readings combined. So, 穴 and 子 to make あなご.