The animal section needs a lot more in the way of acceptable answers. Why is "Fish is delicious" wrong and "A fish is delicious is the only right answer?
You mean, "fish is sweet" as the only right answer... I agree though -- "fish is delicious" or "fish is tasty" does make more sense in context. I'm sure if we've all reported it they'll add the answers in soon :)
It isn't accepting "Fish are delicious" either, though this is technically correct. It marked my answer wrong and changed it to the singular "A fish is delicious."