Can zebra fish live in an aquarium without an aerator?

If you have a zebra danio in a tank, then there will be poisons created by the fish living, breathing, pooing etc in the water. These poisons will need to be removed otherwise the fish will die. There are two common methods of removing these poisons. One is to do regular daily water changes and the other is to use a cycled filter and less water changes. Please remember the basic rule though. "1 inch of fish needs a minimum of 1 gallon of water" so a zebra danio would need a minimum (nominal) 2 gallon tank to live in.