I wish that "shrimp" advice would die the ignominious death it deserves. It has been discredited for years but just keeps coming back.
While it is rotting to create ammonia, shrimp especially, but also fish food can become infested with and grow Saprolegnia mold. While not fatal, it's not healthy. And it's difficult to get rid of.
I recommend pure ammonia that does not
foam when shaken.
Opposite of Waterdog, I'm not a fan of fish-in
cycling. But, assuming a 5g or larger tank, I'd rather do that than use rotting shrimp or fishfood.
Aquarium Nitrogen Cycle and Cycling. Methods for Ammonia, Nitrite Removal.