When setting up your fish tank for the first time, you should have a checklist of things you will need.

Remember that most fish cannot survive in a new tank unless it has been seeded with used filter media. This is because the nitrogen cycle will cause a nitrite buildup that will hurt the fish. A few fish can survive this, but some people like to avoid using fish during this time at all because they may become harmed.

Before putting any water in, make sure that your tank is in the location you want it in. If you try to move a tank with water in it, it could break. 10 and 20 gallon tanks do not need stands and can be placed on desks, tables, or other elevated places. The location of your tank needs to be reasonably elevated or you cannot use the siphoning method to do water changes or to clean your tank.  (A few feet off the ground will do.) For tanks 30 gallons and up, you need a specifically sturdy stand to rest it on. These are provided in fish stores. If you plan on using your own stand, make sure that it can hold the correct number of pounds that your fish tank will be. 

1 gallon of water equals 8.33 lbs. 

If you have sand or gravel for a substrate, rinse it well before adding it to the tank. You can do this with a strainer or by letting water run over it in a bucket for a few minutes, stirring occasionally. It does not matter with these substrates if you add the water or the substrate first. 

If you have a dirt substrate, you will need to add the dirt before adding the water. Adding water too quickly will cause cloudiness. Your filter usually will remove any cloudiness within 24 hours. 

After adding the substrate you can add plants and decorations. These will always withstand the nitrogen cycle. 

Plants will even speed up the nitrogen cycle by helping to break down certain chemicals and adding beneficial bacteria to the tank.