What is the difference between "seafood casserole" and "paella"?
Paella is a specific type of rice dish, cooked in a wide, flat pan. Although sesfood is typical, it can also be made without seafood. (I typically just do chicken and sausage)
Casseroles, however, are typically a higher sided earthware or similar dish, and baked. They typically have starch, but it might be rice, noodles, or a biscuit top. They might use a cream based sauce, or cheese, which would not be included in a paella.
I don't agree with the answer that states
"paella is a specific type of seafood casserole"
A Casserole is cooked in the oven (usually in a casserole dish or dutch oven), a paella should be cooked on the stove top in a paella pan or frying pan.
Pealla is a specific type of seafood casserole. Every square is a rhombus but not every rhombus is a square.