Am I using the expression "A different kettle of fish" correctly in the below example sentence?
The first semester subjects were easy to learn. But the second semester was a different kettle of fish.
Am I using the expression "A different kettle of fish" correctly in the below example sentence?
The first semester subjects were easy to learn. But the second semester was a different kettle of fish.
Yes. You are absolutely correct in your usage.
Idiom Definition 1
"kettle of fish"
an awkward, difficult, or bad situation;
a muddle;
a mess
"kettle of fish"
a state of affairs;
a matter under consideration