Hello and welcome to AA!
A 1 gallon tank is no home for ANY
fish. I encourage you to please tank those white clouds back. They need atleast a 10 gal
tank in my opinion.
I have several 1 gallon tanks and they make lovely planted shrimp tanks. You could get something like red cherry, blueberry, blue pearl, sunkist, or yellow.
The under gravel filter is not a proper filtration system. Do what I did and chuck the thing all together and plug the air pump instead into a small sponge filter you can pick up for just a few dollars that will provide actual biological filtration.
Also a couple granules of fish food and a couple weeks will definitely not cycle a tank. Especially without a sponge or power filter running. The white clouds will surely be poisoned by build up of ammonia and nitrite, especially in such cramped quarters.