Not entirely related to the specific topic of feeding but I thought I'd add a few comments about keeping minnows or any fish alive on a long term basis:
1. Definitely consider getting a charcoal filter system to remove ammonia and other harmful buildups in the tank or bucket in addition to your aerator. You should be able to find cheap ones at any pet store for under $20. If you have a filtration system, you can feed the minnows.
2. Do not change all of the water. Fish create a "biofilter" when they are in the water. It is a combination of bacteria, algae and other microscopic creatures that keep the fish healthy. Think of it as fish broth. If you replace the water with something completely sterile like distilled water, it can shock the fish and kill them. When you are ready to change the water set aside about 1/3 to 1/2 of the cleaner surface water from the current tank and add it to the new water to help keep the biofilter going. Also, consider adding stress coat to the water. You can buy it at any pet store for a dollar or two and need only a couple of drops. It keeps the fish calm and reduces mortality when you change the water.
3. Before you change the water, put the new water in the same place as the tank for a couple of hours so the water temperature is the same. If there is a big difference in water temps, it can shock the fish and kill them.
