Pet food quantity - large package or small package?

Yeah if you can go through a large bag of pet food quickly because you have a lot of mouths to feed, then go for the bigger bags.
For those that a large bag will last forever, it is not a good idea to have it. Although I have over 70 tropical fish, they don't eat much. A single bottle of 2.1oz fish food can last for a year or more. I also feed a variety of fish food for a balanced diet, that would even make each type of food staying around longer. I get the smallest package I can find, but they seem to be still quite big. Maybe I should get more fish instead to go through the food faster, so I can buy fresh food more frequently.