Setting up your freshwater aquarium should be fairly easy. Make sure that you have all the things that you need, including a water conditioner such as Seachem's Prime or Kent's Freshwater First-Step. You will also need to have an aquarium heater, thermometer, some good filtration,( I would NEVER use or recommend undergravel filtration ) gravel,and some power heads or air curtains to agitate the water's surface and allow the oxygen exchange to take place and perhaps some decorations. The decorations should include some items that are large enough for smaller or more shy fish to hide in. And surely, you will want some type of aquarium lighting to view and to enhance the colors of your fish.

Things you will need to know:

You will need to know, based on the size of your aquarium, how many fish you can safely keep. Just as we do, fish utilize oxygen and too many fish in a tank would jeapordize all the fish. You will also need to know the compatibility of the fish. Some fish are very shy and docile while others can be semi-aggressive and many can be very agressive. Determine what kind of fish you are going to keep and stick with either community fish or those that are aggressive. Find a few good foods for your fish. Feed only what they can eat in a few minutes a few times per day and make sure that you are not feeding them the same food at every feeding. They, too, like a little variety. Some fishes diets require it.

GETTING SETUP:

1) If using hang-on filtration, put into place on the back or side of the tank. If using cannister filtration, set it up to where it is easily accessible for filter or media changes.

2) Decide where you want to have the powerheads near the water's surface or place air curtain in tank using suction cups or anchors to keep it in place once water is in tank.

3) Put the gravel in the tank and then lay decorations into place.

4) The submersible heater can sometimes be easily hidden behind the decorations. In any case, set the heater to the temp of the environment you are trying to achieve and find a place in the aquarium to place the heater where there is sufficient water flow to prevent any 'hot spots.'

5) Fill tank with water to capacity and add water conditioner based on manufacturer's recommendations.

6) There are a number of thermometers on the market. Some are submersible, some float and others sink. There are also digital thermometers that attach to outside of tank with a probe that is placed in the water. Find a good place for the thermometer to that it can be easily read at any given time.

7) With everything in place, start up the system. Run it for a week, checking the temperature to make sure that you haven't overshot the ideal temperature that you were trying to achieve. If so, unplug and make adjustments on the heater.

After a week of watching your beautiful tank with nothing in it, you can begin to add your fish....a few at a time. Your system will undoubtedly go through a nitrification process of building helpful bacteria that will reduce toxic wastes like ammonia and nitrites to a less toxic product called nitrate. Your local fish store ( LFS ) would probably be happy to test a sample of your water. If not, test kits are readily available and are fairly inexpensive.

Keeping your tank clean and the inhabitants healthy are very important. You can achieve both by doing periodic waterchanges by using a gravel vacuum to keep the gravel free of waste and debris. I would recommend a 10% water change using the gravel vacuum at least once a month and of course, adding conditioned water ONLY to the tank to make up for water removed by the change. Any water discoloration can be removed by the use of activated carbon. If you take the care to replace the filters in your filtration unit as needed, this should reduce any likelihood of that scenario.