NOTE* This project involves live animals. No animals were harmed in the making of this instructable. Also, do not try this with just anything. I chose a pretzel container because it was for food, and therefore shouldn't kill fish. I would have been deeply worried if the fish had died due to the plastic, since we eat food from it.
Step 1: Gather materials
1. empty pretzel jar, or other food grade quality container.
2. small air pump(for circulation)
3. aquarium gravel
4. air tubing, air stone, and air flow valve.
5. something able to cut and poke holes(i used a swiss army knife)
6. thermometer for water temperature
7. access to a sink, and possibly a hose as well.