I usually don't bother much in Friday because it is the end of a school week. My folks are not fish lovers and they don't prefer to have seafood all that often.
This is a reason why I sometimes substitute the fish with the poultry, chicken or turkey.
Usually I have predefined weekly menu except for Sunday. Then I like to experiment and surprise my folks with the new food.
I cook main meal once a day and split it for lunch and dinner.
Extra food listed is between the meals, either as a breakfast or between lunch and dinner.
If like it, I don't have any breakfast.
For Fridays I like to prepare the grilled fish, because I find it the most interesting and fast. Compared to other techniques, I waste shorter time.
Aside of the grilled fish I cook potatoes with swish chard, seasoned with the olive oil and salt.
This is pretty easy to do and doesn't need a MasterChef level of the cooking skill. I will not say it is cheap, because the fresh fish in my local markets is not cheap.
I don't like to prepare deep frozen fish because the taste can vary. And some fish gets pretty wakeful odor by staying in the ice.