What kind of company should a good student keep?

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:

6  then the  lord  said to cain, “why are you angry?   why is your face downcast?   7  if you do what is right, will you not be accepted? but if you do not do what is right, sin is crouching at your door;   it desires to have you, but you must rule over it.”

8  now cain said to his brother abel, “let’s go out to the field.”  while they were in the field, cain attacked his brother abel and killed him.