Article: Crowding too much bait into a container can cause the bait to die more quickly. Too many fish will deplete oxygen quickly and create too much heat. For example, only put about six dozen small minnows (3/4' to 1" long) in an eight-quart container. For example, you can store your bait container in a closet or a basement. Minnows are delicate and thrive better in cooler water. The water will warm up too quickly if you keep the cooler in a bright area. An aerator will add oxygen to the water so that the minnows don't use it up and suffocate. This is especially important if you need to keep the fish for a day or two, and if you don't plan on switching out the bait container water often. Those that sell minnows commercially usually use an aeration system that oxygenates their water in one of two ways: agitation or compressed oxygen. An aerator can help to increase the lifespan of your minnow. This is due to the fact that other ways of aerating the water, such as adding additional water or adding hydrogen peroxide, can stress the fish immensely. With an aerator, the minnows get to simply stay in the water that you have already acclimated them to. You only want to add one ounce of three percent hydrogen peroxide solution for every three gallons of water. The hydrogen peroxide assists in the formation of oxygen in the water, replacing oxygen that is used up by the fish. You can also add more distilled water as necessary to refresh the minnows' water. Adding hydrogen peroxide to water is a controversial idea. Some people believe that it helps to oxygenate the water and won't hurt fish but others argue that it could kill fish easily. If you are unsure or apprehensive about adding it to your minnow's water, find an alternative, such as an aerator or changing the water frequently. Place ice cubes in a jar in the water that's inside the bait bucket to keep it sufficiently cool for the minnows. Repeat this as often as necessary to keep the water cool. Although minnows can survive in warm water, the rate of death increases dramatically once holding water is above 60F (15.6C). Try to keep your water below this temperature. Don't add ice directly to the water the minnows are in. The ice may contain small amounts of chemicals or chlorine that will kill the fish.

What is a summary?
Don't overcrowd your minnow tank. Store the container in a dark, cool spot. Put an aerator in the container. Pour a small amount of hydrogen peroxide into the cooler if you do not have an aerator. Keep the water cool.