Duolingo is right: 듀어린고는 가끔 이상해요.
Because they're always weird
Apparently they're edible, though I can't imagine they're worth the effort. Perhaps it works for owls...
Apparently, you are correct. Although they aren't palatable to humans as water has more taste than their meat. I'm saying this out of experience.
It's a common dish in my country but I guess the word "goldfish" itself kills my childhood cause I imagine the fairy odd parents being a dish.
There should be no space before "입니다."
Why is there a space between 금붕어 and 입니다?
That's what the goldfish gets for coming early...