Ratiocination can you revise your work by getting you to

focus on one element of your writing at a time

the word that best matches the meaning of the expression "went to the big ocean" is died.

the goldfish died, which is why the father looks at the children mournfully. the "big ocean" is the father's way of saying fish heaven. he could have just said that the goldfish died, but this way, the children imagine the fish in a bigger, better place instead of just picturing a dead fish.

explanation:

this quote could be referring to the death penalty. it's questioning the morality of sentencing murderers to death as a punishment, because it seems hypocritical. this quote seems to be arguing for non-lethal punishment for killers.