Most non-vegetarian Indian homes do not eat meat at every meal, and a plan that pretends otherwise is both expensive and exhausting to cook. This week puts meat or fish in one main meal a day and keeps the other one vegetarian, which is how the food actually shows up on the table.
The meat is spread deliberately: chicken on Monday and Tuesday while it is freshest, fish mid-week and Friday, eggs wherever a quick meal is needed, and mutton reserved for Sunday lunch when there is time to cook it slowly.
Grocery quantities are for a family of four. Buy the fish on the day it is cooked if you can — otherwise clean it, portion it and freeze it the day it comes home.