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How to Set up a Fish Tank: A Beginner's Guide

Having worked with fish most of my life, I have a strong desire to help others to be successful in the hobby.

A healthy tank with Neon Tetras.  Note the oxygen being produced by the healthy plants in the tank.

A healthy tank with Neon Tetras. Note the oxygen being produced by the healthy plants in the tank.

Starting a Fish Tank for Beginners

Years ago when I worked in the aquatic section of a pet shop, I would often have customers come into the store and tell me that they had purchased an aquarium (usually from somewhere else) and set up their tank, only to have their fish die soon after.

Setting up and maintaining an aquarium is actually quite easy if you understand the needs of the fish and how to keep them healthy.

How to Prepare for a Successful Aquarium and Healthy Fish

It can be quite tempting to see a fish you really want and purchase it before the preparations have been made for it to have an ideal home. If you really care about the fish and its well-being, try to avoid the urge to purchase it until you have made the proper preparations. This will help ensure a healthy, long life for your new pet.

Learn About the Water You'll Be Using

Knowing a little about your water will give you an advantage when selecting fish. For example, if you have very soft water, some fish (like guppies) are likely to have more problems than fish that prefer soft water, such as tetras, rams, angelfish, or discus.

Is Your Water Treated?

You may wish to call your municipality where your water comes from to find out how your local water supply is treated. Most municipal water supplies have chemical additives in them such as Chlorine or Chloramine, both of which can be harmful to the beneficial bacteria in your aquarium and can be harmful to your fish. Chloramine, in particular, poses issues for aquarium hobbyists as it is a mixture of chlorine and ammonia. Ammonia is highly toxic to aquarium fish.

If there is chloramine in your water supply, some products used to dechlorinate your water will not be effective against the ammonia in chloramine. Water conditioners that specifically say they are useful in treating water with chloramine will be needed to treat any water that goes into your aquarium if there is chloramine in your water supply.

What's the pH and Hardness of Your Water?

You may also wish to find out more about your water such as pH or hardness of your water. You can purchase test kits for testing your water, or some pet shops will test your water for you.

Learn About the Fish Itself

One of the most important things you can do in preparing to be a successful fish keeper is to learn everything you can about the fish you are interested in. By studying the fish, you can learn a number of important things that will affect your aquarium setup, such as the following:

  • What size tank the fish will require as it ages
  • The water it needs
  • Its food requirements
  • What other fish can be kept with it
  • How to breed it (if you wish)
  • Any other needs that are specific to that fish

Learn About the Live Plants You Want in Your Tank

If you decide you would like to use live plants, which I would highly recommend for most aquariums, you will want to study which plants (if any) would work best for your situation and how or if they should be planted.

Besides the benefit to the aquarium the plants provide, they can also be propagated. Our Cryptocoryne wendtii started as just one plant several years ago, and now we have hundreds.

Many plants have special lighting needs and may also require the use of CO2. Beginner aquarists may wish to look for a plant that doesn't have special lighting requirements and doesn't need CO2. One of my favorites is Cryptocoryne wendtii, which requires little care in my tanks.

Trimming the roots from plants we are dividing for use in other aquariums

Trimming the roots from plants we are dividing for use in other aquariums

How to Set up the Aquarium

You will want to set up your aquarium long before you purchase any fish for your new tank.

Purchase the Basics: Substrate, Ornaments, and Plants

Choose the type of substrate or gravel you will want to use and select any ornaments you will want to use in your tank. Be sure to select only ornaments that are safe for aquarium use. Some items that are not designed to be used in an aquarium can be toxic to your fish.

If you are going to use plastic plants, these can be purchased at this time. If you want to use live plants (I prefer live plants), then you may wish to wait a few days before purchasing them.

Wash the Tank, Gravel, and All the Ornaments

Thoroughly wash all of the items you are going to put in your aquarium. Any item you choose to place in your tank should be safe for aquarium use. Never use chemicals to clean your aquarium or its contents. Only warm water should be used to clean these items. Soaps or detergents can be toxic for your fish.

I like to use a 5-gallon bucket to clean aquarium gravel. Stir the gravel, drain, and repeat the process until the water is clear.

How to Select an Appropriate Location for Your Aquarium

Where you decide to place your aquarium can have a significant impact on how much care your aquarium will need and can even affect the health of your aquarium fish.

The Location Should Be Safe

Select a location where your aquarium is safe from little children that could unintentionally get injured by the aquarium or electrical appliances around it. Small children should be supervised around the aquarium as it can be dangerous both for them and for the fish.

High traffic areas should be avoided. Setting up an aquarium at an entryway or other high traffic area leaves your tank at risk of being bumped, knocked over or cracked.

Ideally, there should be a GFCI circuit protecting you, your fish, and your aquarium equipment installed in the location you desire to put your aquarium. In the United States, there are several GFCI products available today that are designed for aquarium use. These products plug directly into a regular household outlet so that an electrician is not required.

The Location Should Offer Easy Access

Your aquarium should be placed in a location where you can get to it easily at least two times a day and should have enough space around it that periodic maintenance can be performed.

Try not to put your aquarium in a location where it might be forgotten or neglected.

The Location Should Not Be Near Windows or HVAC Vents

Avoid putting the aquarium near a window where it will get direct sunlight. Putting your tank near a window will make it difficult to control the amount of sunlight the tank receives and will likely result in excessive algae growth.

Locations near a window tend to have higher fluctuations in temperature than other parts of the home. This can affect the overall health of the aquarium fish, and in extreme cases high or low temperatures can be fatal for the inhabitants of your aquarium.

Heating and cooling vents can also create rapid changes in the temperature of the items directly around them or cause them to be extremely cold or hot. Try to keep your aquarium a few feet away from these HVAC vents.

The Location Should Be Able to Support the Weight of the Aquarium

Another consideration is the weight of the aquarium and if the floor that is supporting the aquarium, lights, pumps, stands, and other equipment can withstand the weight over a long period of time.

Aquarium water weighs approximately 8.34 pounds per gallon of water. Adding in all of the substrate, decorations, stand and equipment, a 55-gallon aquarium could weigh more than 500 pounds!

How to Select a Stand

In most cases, you will want to keep your aquarium on a stand of some type so that it is easier to see the fish. Stands can be purchased or handcrafted. Be sure that your stand is level and is able to withstand the heavy weight that comes with the water and ornaments found in an aquarium.

An aquarium placed on a stand that is not level may crack or separate. It can be surprising how much water is in the aquarium once you see it all over the floor. Yes, this is experience speaking!

Aquariums placed on a stand can be quite top-heavy, leaving them easy to tip over despite their heavy weight. We use a small metal bracket and screws to secure our aquarium stands to a stud inside the wall they are against to help prevent the stand from tipping over.

How to Fill the Tank

Once an appropriate location is selected you can now start to fill the tank.

1. Add Substrate

Starting with the gravel or substrate that has been washed and ready for use. Depending on the way you set up your tank and the type of filtration system you use will determine the amount and type of substrate you will want to use.

I like to use two inches of black CaribSea Flora Max Planted Aquarium Substrate or similar product in my aquariums as I feel it helps promote beneficial bacteria growth and has been a good substrate for the plants I like to keep in my aquariums.

2. Add Some Water

Once your substrate has been placed in the tank, you can now add 2–3 inches of water. I like to place a small plate or saucer on top of the substrate so that it doesn't get washed away and stays in place.

3. Add Ornaments

Now you can add any ornaments or filtration equipment you wish to add to your aquarium.

If your filtration equipment requires an air line be sure to install a check valve in it to prevent water from siphoning out of your tank and into the electrical components of your air pump in the instance of a power outage.

Plastic or live plants can be added at this time; however, I prefer to wait for the water to stabilize a couple of days before adding live plants. This gives time for the water to age a little and to make sure the water heater is operating correctly and at the appropriate temperature.

Now is a good time to add the water conditioner or de-chlorinator to your aquarium water.

4. Add More Water

Now your tank is ready to finish filling. Placing your clean hand between the water stream and your aquarium will help keep the water from knocking around your aquarium gravel and ornaments. Be sure to leave a little space between your aquarium cover and the water so that air can be exchanged at the surface of the water.

5. Turn It On

Turn on your light, water filtration system, and heater and make sure everything is working correctly and safely. The aquarium heater should be installed in accordance with the manufacturer's instructions for safety and to prevent damage to the heater.

Be sure to have a thermometer available so that you can check and adjust the heater in the aquarium. It can take several hours for the temperature to stabilize. Be sure to wait long enough for the water temperature to stabilize each time you adjust the water temperature.

6. Add Live Plants

Although it's easier to plant the live plants at the same time the ornaments are placed in the tank, I prefer to add them after the tank has had time to stabilize for a couple of days. This ensures that the temperature is stabilized for the plant.

Do Not Add Fish Yet!

Although it's tempting to add fish to the aquarium at this point, it's not ready for the fish as the tank needs to be cycled.

The Nitrogen Cycle

One of the most important things to understand about an aquarium is the nitrogen cycle.

In order for your fish to stay healthy, your aquarium must have a good nitrogen cycle. This process may take several weeks or months to complete.

Stage 1: Ammonia

Ammonia can be deadly to tropical fish by burning their gills and skin and making it difficult for them to breathe.

As soon as you add fish or plants to your aquarium, ammonia is starting to be produced in your aquarium.

Decaying plants, uneaten fish food, and fish waste all contribute to the production of ammonia in the tank.

Stage 2: Nitrites

Often when we think of bacteria, we think of something bad or dirty. Bacteria is vital for the health of the aquarium and the fish that are in it.

There is not just one type of bacteria, but many are harmful in an aquarium, but many are beneficial and are required for aquarium health.

If given the opportunity, a bacteria called Nitrosomonas will start to develop in the aquarium. These bacteria help to convert harmful ammonia into nitrites.

Some types of Nitrosomonas bacteria do better in an aquarium environment than others. Because of this, adding large amounts of ammonia to the aquarium it may cause the aquarium to take longer to cycle than it would have if no ammonia was introduced.

Unfortunately, Nitrites are also toxic to aquarium fish.

Stage 3: Nitrates

Soon another type of bacteria will start to do its work of converting nitrites into nitrates.

Nitrates are not as harmful to fish as nitrites or ammonia as long as concentrations of nitrates don't get too high.

Live plants can help reduce the nitrates in the tank, but the easiest way to control nitrates in an aquarium is to do partial water changes.

Using an aquarium test kit will help you to monitor the water quality in the aquarium and help to determine when water changes need to be done.

I prefer the API Freshwater Master Test Kit over paper test strips. This kit help you to monitor pH, ammonia, nitrite, and nitrate.

A good rule of thumb is to change 10% to 15% of the water once a week however this can vary greatly depending on the number, size, and type of fish that are in the aquarium.

The way the aquarium is set up and filtered can also greatly influence how often partial water changes should be done.

Easy to use aquarium vacuums are ideal to help do the partial water change as well as clean up excess debris from the bottom of the tank.

Common Beginner's Mistake: Complete Water Changes

One of the most common mistakes I've seen time and time again for beginners is performing complete water changes.

Completely removing all the water from the tank doesn't completely kill all the beneficial bacteria in the aquarium; however, it does disrupt the nitrogen cycle.

The need to do full water changes is usually caused by trying to put too many fish in an aquarium before it has a chance to develop the nitrogen cycle.

Overloading the Nitrogen Cycle

Adding too many fish to your aquarium at one time overloads the nitrogen cycle causing an overabundance of bacteria and depleting the tank of oxygen for the fish.

Another common mistake that overloads the nitrogen cycle is overfeeding your fish. You should never feed your fish more than they can eat in a two-minute period.

When bacteria levels get too high, the water becomes cloudy, and the fish start to show signs of having difficulty breathing. If left untreated, the fish will soon die.

Advantages of Modern Aquariums

Fortunately, modern filtration systems in today's aquariums help to make the process of keeping a healthy aquarium much easier.

Most modern filtration systems have three parts to them that help to ensure a healthy environment for your fish.

Mechanical Filtration

Mechanical filtration removes large pieces of material from the tank by physically trapping them with material that is designed to act as a sieve to strain out the larger particles from the water.

This mechanical filter often looks like a sponge or fibrous material.

Cleaning mechanical filters can be done by removing them and rinsing them off to be reused.

Chemical Filtration

Chemical filtration uses substances to help remove substances dissolved in the water that cannot be removed by mechanical filtration.

One of the most commonly used chemical filters is activated charcoal.

Although these chemical filters may be helpful in a new aquarium, I am of the opinion that a healthy cycled aquarium does not require chemical filtration and may even be somewhat harmful to a well-cycled aquarium.

Biological Filtration

Numerous products are available to help improve biological filtration. These products are highly porous, giving a greater surface area for beneficial bacteria to grow.

This is where much of the ammonia and nitrites are removed using the nitrogen cycle.

Biological filtration can occur in a number of locations besides the filter itself. Depending on the type of substrate used in an aquarium, the substrate can perform substantial filtration.

Tank Setup Example

I recently set up a tank that I will be using to raise Class N Endler's Livebearers. These fish are very easy to care for but do like to have lots of plants for the fry (babies) to hide in.

Preparing the Tank

I was very fortunate to acquire a 12-Gallon AquaPod aquarium at our local thrift shop for only $10. These tanks are almost always used to set up a saltwater aquarium but will work very well for freshwater use.

Because the tank was used, it was important to make sure that there were no diseases leftover from the previous occupants.

To make sure the tank was properly cleaned, I filled the tank with water and a gallon and a half of hydrogen peroxide. Fortunately, our local Walmart sells quart-size bottles for only $0.88 a bottle.

Hydrogen peroxide will break down over a 24 hour period into water and hydrogen, leaving no harmful chemicals in the tank and is highly effective in killing any diseases that may be left in the tank.

I ran the pump and let the hydrogen peroxide and water mixture sit in the tank for 24 hours.

After 24 hours, I emptied and washed out the tank with warm water.

Foam filter media I cut to size for use in my new aquarium setup.

Foam filter media I cut to size for use in my new aquarium setup.

Adding the Filter Media

I then added the filter media. This particular type of tank actually has the filter system built into the tank; however, because this was a used tank, it did not come with any filter media.

I then went to our local pet shop and gathered some of the things I needed for the tank.

The first thing I needed was a mechanical filter media. I found a sponge-like filter media that was big enough to fill the opening in the tank and cut it to fit perfectly. I had to purchase and cut two of them to get the filter to effectively cover the opening of the next chamber.

At this point, I stopped adding filter media because I did not need the chemical filter yet, and I did not find an affordable option for a biological filter in the pet shop.

These small "Bio Balls" have foam squares inside.  Very reasonably priced out of China.

These small "Bio Balls" have foam squares inside. Very reasonably priced out of China.

Finding the Biological Filter Media

Because I couldn't find affordable biological filter media at my local pet shop, I went to eBay to see what I could find.

I was able to find some affordable 16mm Bio Balls that had sponge in the center that I liked and were at a very reasonable price.

Unfortunately, the Bio Balls had to come from China, so I had to wait a week before adding them to my tank.

While I was waiting for the bio Balls I also ordered some filter media bags to put the Bio Balls into.

The bag I received was fairly small, so I'll probably order a couple more in the future.

Choosing the Substrate

The substrate is the material that you use for the bottom of the tank, such as gravel or sand.

Because I wanted to use live plants in my aquarium, I purchased Black Floramax Premium Aquarium Substrate.

I chose this brand because it was the only brand that was available in my area that looked like it would be beneficial to my plants and would be porous enough to encourage bacterial growth.


The hardscape is the decorations you put in your tank, such as rocks or driftwood. These pieces form the main focal points for your aquarium.

In my case, I used a piece of black and white marble that I collected from southern Arizona. I cleaned the rock well before using it in the tank.

To make the rock look more natural, I partially buried it in the substrate.

Aquarium Plants

The fish I plan to add to my tank really like to have live plants to hide and feed on. I selected a few plants that would be easy to keep in the tank and gave the aquarium the look I wanted.

Fortunately, the tank I'm using has a great lighting system for the live plants.

One of the plants I selected was Dwarf Hairgrass; I purchased one package and then separated it into small clumps and spaced them somewhat evenly throughout the front of the tank.

If the Hairgrass does well, it should form a carpet of green in a few months.

Depending on how things go, I may make a homemade CO2 system for the tank at a later date.

Preparing Hairgrass for Planting

Small Green Cory Cat added to aquarium two weeks before adding more fish.

Small Green Cory Cat added to aquarium two weeks before adding more fish.

Adding Fish to the New Aquarium

After letting the plants adjust by themselves for a week I added one fish, a small green Cory Cat. This will help get the nitrogen cycle going while I wait to add more fish.

After a couple of weeks, I ordered my Class N Orchid Endler's Livebearers and added them to the tank. Of course, I set the bags with the fish in them in the tank for 15 minutes to allow the water temperature to equalize as always.

At this point the tank should pretty much take care of itself other than some partial water changes, cleaning of glass and other surfaced and periodic changing or cleaning of the filter media.

Below is a picture of the tank just after adding the Orchid Endler's Livebearers.

Questions & Answers

Question: I was wondering if I could use gravel from a goldfish aquarium in a new tank to help seed it? Will it harm any tropical fish?

Answer: As long as the gravel stays wet and you are sure it’s free of illnesses or parasites, that should work well.

Question: Does the temperature strip go inside or outside the fish tank?

Answer: The temperature strip goes on the outside of the aquarium however a more accurate method of measuring the temperature is to use an actual thermostat that goes on the inside.

© 2013 Marty Andersen