15 Things You Must Know Before Buying Your First Aquarium

Buying your first aquarium is very exciting.

But for most people, their experience with their first fish tank doesn’t go quite well.

Most people mess up with their first aquarium and this can even cause the death of your pet fish.

But this can be easily avoided by pre-planning and making a simple checklist of what things you will need.

In this article, I am going to share with you everything you need to know before buying your first aquarium.

Things to Know Before Buying Your First Aquarium

things to know before buying your first aquarium

1. Saltwater or freshwater

Before purchasing your first aquarium you need to figure out which kind of fish tank you want to have.

There are two types of fish tank you can have

  1. Freshwater fish tank
  2. Saltwater fish tank

Generally, freshwater fish tanks are very easy to maintain and set up than saltwater fish tanks.

But saltwater fish tanks are more colorful and vivid than the freshwater tanks.

The best way to figure out which kind of aquarium will be good for you is to just by visiting the nearest pet store and look through all the fish on the display.

And choose the one which you like and then find out its saltwater or freshwater.

Are Tropical Fish Tanks Hard to Maintain?

2. Every Fish is Different

Once you have figured out you want to have a freshwater aquarium or saltwater aquarium.

Then it’s time to look for the fish to put into your tank.

If you have done the above exercise of looking through the displayed fish then most likely you will know which fish you like in your aquarium.

Remember that not all fish are the same.

Every fish require a different water condition or at least every kind of fish require different water condition and environment.

For example, Goldfish and Betta fish are both freshwater fish but Goldfish require cold water and betta fish require warm water.

3. Acclimate the Fish

You have to acclimate the fish before you introduce it into your fish tank for the first time.

The temperature of your tank and the temperature of the water of the bag in which your fish was is different.

So when you directly introduce it into your aquarium it may shock your fish which can even cause death.

There are many ways to eliminate the fish but the simplest way is to just hold the unopened bag which contains the fish on the surface of your tank for 15 to 20 minutes.

And then put the fish into the tank using your hand.

Remember, you don’t want to introduce the water of the bag in which your fish was into your aquarium because this water may contain a lot of ammonia which you don’t want in your tank.

4. Know Your Fish

Once you have decided which fish you want to put into your aquarium then it’s time to get into some nitty-gritty of your fish.

You should do some research on your fish and find out the following things:

  • What kind of water conditions does it require?
    • What is the ideal condition for the fish?
    • What is the water pH tolerance range of the fish?
  • Is there any special food it requires?
    • For example, Goldfish food contains more carbohydrates and less protein whereas the generic Goldfish contains more protein and low carbohydrate. So, in this case, any generic food is not good for the Goldfish.
  • How much space do they require?
    • For example, Goldfish require at least 20 gallons for its optimum growth. and if you have a small Goldfish then 5 gallons per inch is a good rule of thumb to follow. If you put the Goldfish in a small tank for fishbowl then its growth will be stunted i.e. it will not grow to its full potential.
  • What other fish can be kept with your fish?
    • For example, Rosy barbs and Dojo loaches are very good mates for the Goldfish because they require the same water condition as Goldfish. And Corydoras and Cichlids are not good for Goldfish because they are aggressive.
  • What are some best plants for your fish?
    • Some fish like Goldfish really like plants in their aquarium. If you are planning to add some plants in your tank then you should also first know what are some good plants you can put with your fish. Because you can’t just throw any plant in your tank. The plants also need a particular water condition to thrive. So make sure that the plants are comfortable with the water condition your fish require.

5. How Much a Fish Tank Cost

Once you figure out which fish you would like to put into your aquarium then it becomes a lot easier to find out the actual cost of the aquarium.

Depending on the fish and how many fish you want to put into an aquarium the size of the aquarium varies, the food you need to feed varies and the equipments you will require also varies.

It all may seem like a puzzle that you need to figure out.

But in reality, it is not that complicated.

A fish tank requires regular maintenance.

You just can’t set up a fish tank and forget about it.

So it’s not a one-time thing and things in the aquarium will change over time.

So now let’s see how much it’s actually going to cost you.


How much the fish will cost really depends on what fish you have chosen and what size of fish you want.

For example, you can get a common juvenile Goldfish for $1 and an adult can cost you $30.

Also, there is a lot of expensive fish like freshwater stingray that can cost $200 for a juvenile and $2,000 for an adult.

Fish tank

The fact is big aquarium is easy to maintain than a small aquarium.

So if you are just starting out and this is your first aquarium then you should not buy a small fish tank of 5 gallons or less or a fishbowl.

Because the water chemistry changes really fast in the small tank or fishbowl and it will not provide a sufficient amount of time for you to figure out the problem and fix it.

For example, if you use a fishbowl for your Goldfish then, first of all, it is not a good idea because as mentioned above Goldfish requires a lot more space than a fishbowl for its optimum growth or it will get stunted.

Overall, a fishbowl cannot provide a healthy environment for its growth.

Goldfish is a pretty messy fish so the ammonia level can really rise quickly in a fishbowl which can cause even the death of your Goldfish and really any fish.

Besides, a small tank or fishbowl can hold a very small amount of oxygen.

If there is a shortage of oxygen then fish will suffocate and die.

Also, you can’t really do much with a small tank or fishbowl, like keeping live plants and various ornaments or decorations to make it look beautiful.

So I highly suggest you get at least a 10-gallon tank or if possible get a 20-gallon tank. Because it will be a lot easier for you to maintain it.

And even if you mess up something there will be sufficient time for you to make required arrangement to fix it.


There are various types of filters available for the purification of your aquarium water.

Filters provide space for the growth of beneficial bacteria.

The beneficial bacteria is the bacteria that helps to reduce the ammonia in your aquarium

There are several types of filters available for the aquarium as follows:

Canister filter

This filter sits outside the aquarium so it will not take any space inside your aquarium, which makes it ideal for 10 to 20-gallon aquarium because the space is very limited in these aquariums.

These filters are bulky in size but they are also very powerful. 

Also, some canister filters come with a spray bar that helps to oxygenate the tank.

These filters are a bit noisy.

Hang on the back (HOB) filter

As the name suggests, these filters sit on the back of your aquarium.

Basically, you have to hang it on the age of your tank.

Usually, half of the filter is submerged in the water and the other half is outside the water.

The part which has the motor is usually submerged in the water which makes it pretty quiet.

Another cool thing about this filter is that the filtered water coming out from this filter usually falls from some height into the aquarium so the water gets exposed to the air which helps to oxygen it.

This filter is relatively smaller in size than the canister filter, it does pretty good filtration and it is very quiet as well.

If you are going to buy a 10-20 gallon tank then I suggest you get this for your tank.

Internal power filter

As the name suggests, these filters are fully submerged in the water so they are very quiet.

Basically, you have to hang it inside the tank so it will take some of the space of your aquarium.

This filter is very cheap and easy to maintain.

Overall, internal filters are good for a 10-20 gallon tank.

If you are going to buy a bigger tank then it will not very effective but still, it will be good during an emergency, when your other filter stops working, etc.

Undergravel filter

As the name suggests, this filter is placed under the gravel of your aquarium.

This filter is very quiet and as it is hidden under the gravel, it will not mess up the look of your aquarium.

These filters are not as effective in filtering the water and they are very old fashioned.

If you are very concerned about the look of your aquarium then this could be a good choice for you.

Sponge filter

As the name suggests, this filter is mostly made up of sponge.

This filter is consists of the plastic housing and an air pump.

The air pump blows the water through many layers of sponge which filters the water.

These are effective filters but you have to regularly clean the sponge because it gets dirty very fast.

Also, it is a very bulky filter so it will take some of the valuable space of your aquarium.

So these are the various filter available for the aquarium.

If you are going to purchase a 10 to 20 gallon aquarium then I suggest you to go for a Hang On Back (HOB) filter or canister filter.

If you are planning to get a bigger aquarium then and you should definitely go for a powerful canister filter.

The cost of the filters really depends on the tank of your aquarium.

The HOB filter is usually cheaper than the canister filter.


A fish tank weighs a lot when it’s filled with water.

A 10-gallon aquarium weighs about 111 lbs and a 20-gallon aquarium weighs about 250 pounds when filled with water.

So usually placing your fish tank on the desk is not a good idea because it may not be able to bear the weight.

So you can go for stands specially made for aquariums.

Aquarium stands come with an additional compartment so that you can put other equipment like fish food, cleaning tools and canister filter in it.


The substrate is not a must-have thing when it comes to aquariums.

But it really helps emulate the natural habitat of your fish.

The substrate also provides a place for the growth of beneficial bacteria.

If you are going for a saltwater aquarium then Marine sand and lives sand is good substrate for your aquarium.

If you are going for freshwater aquarium then you have two options

  1. Fine gravel
  2. Coarse gravel

If you are planning to put bottom feeders in your aquarium then you should go for fine gravel. Just make sure that the ages of the gravel are not sharp so that it will not harm your fish.

If you are going to put big fish like Goldfish, South American or Central American cichlids then you can go for coarse gravel.


There is a mixed opinion on you need a heater for your aquarium or not.

There are some good benefits of using a heater though.

  • It provides a stable temperature in your aquarium
  • Some species of fish require a certain temperature for spawning that a heater can help to provide.
  • Also, some species required a certain temperature for an even split of the gender ratio of the offspring so a heater can help with that.
  • Heaters also helps in disease treatment.

But do you need a heater for your aquarium?

Honestly, there is no one answer for everybody.

There are some questions you need to ask and find out their answers to know if you really need a heater for your fish tank.

  • What fish are you keeping and what’s the ideal temperature for it?
  • Where does your fish come from and in what weather condition it live there? 
  • Where do you put your aquarium in your home and what temperature can you maintain in your aquarium?
  • Also, you should know what are your goals for your aquarium. Do you just want to keep the aquarium or do you want to breed your fish? (Some fish require certain temperature to spawn)

Once you have the answer to all the above questions then it will be a lot easier for you to decide if you need a heater or not.

There is a wide range of prices when it comes to a heater for your aquarium depending on the functionality and brand.

If you are going to get a fish tank under 20 gallon then you can find a good heater under $50.

Check out our recommended heater

Air Pump

An air pump is not a must for your aquarium if your tank has a sufficient amount of oxygen.

If your fish tank has enough water agitation then it will carry a sufficient amount of oxygen for your fish.

There are various signs that tell you low oxygen in your aquarium.

If you noticed your fish coming on the surface of your fish tank gasping for air then it is a sign that your aquarium has low oxygen.

In this case, you will require an air pump.

An air pump is relatively cheap and its cost depends on the size of your tank.

You can find an air pump under $20 for thank as big as 200 gallons.

If you have a 10 to 20-gallon tank you can easily get an air pump for it under $10.

Besides oxygenating the tank air pump also has several other benefits.

  • It helps to remove dead pockets from the tank.
  • It helps to maintain a constant temperature throughout the tank.

Check out our recommended Air Pump


If you are planning to put some plant into your aquarium then you will require lighting for your aquarium.

Depending on the plant you will require strong lighting or dim light.

If you are not putting plants into your aquarium then you don’t really need lights for your fish.

The natural light coming in the room will be sufficient for your fish.

If you do plan to put some plant into your aquarium then make sure that the lighting is low at the beginning and then you can gradually increase it over time.

This is because. initially plants don’t require much lighting. 

In fact, too much light can shock a plant. 

Also, the algae will take the benefit of the light and will grow very fast which we don’t want.

Light with adjustable lighting functionality is very convenient to dim the lighting and then increased gradually.

Also, don’t keep the lights on for more than 12 hours because fish like to sleep in dark.

Lighting can be very expensive. 

Depending on the brand and functionality it will cost anywhere from $30 to $80 for a small tank.

In big tanks, people usually use customize lighting because it can increase electricity bills a lot!


Plants are not essential for a healthy fish tank. But there are a lot of benefits of keeping plants in your aquarium.

Benefits of plants in the aquarium

  • Oxygen– This is probably the most important benefit of having live plants in your aquarium. Plants produce oxygen for your fish for their of optimum growth.
  • Reduce algae growth– Plants require the same nutrients as algae so if you keep plants in your aquarium then it will help to reduce the growth of algae in your aquarium.
  • Hiding places for your fish– Plants helps to emulate the natural environment of your fish. They provide hiding places for your fish. Usually fish like to sleep near plants because it gives them a sense of security.
  • Aesthetic look– Plants offers you a chance to personalize your aquarium and give it a unique and interesting look.
  • Food– Some fish like Goldfish like to nibble on plants and it is a good source of nutrients for them.

While selecting plants for aquarium, just make sure that it is compatible with your fish and it can survive in the water condition that is favorable for your fish.

Depending on the species and size of the plant, the price will vary from 10$ to 30$.

Cleaning stuff

You will also require tools and chemicals to maintain a healthy aquarium.

If you are going to put substrate in your aquarium then you will require a siphon to clean the gravel.

You can clean the aquarium manually by using a fishnet but it is not that effective and a siphon makes the cleaning very convenient. Check out our recommended Vaccum Cleaner or Siphon

If you are going to use tap water for your aquarium then you will require a dechlorinating agent to dechlorinate the tank. Check out our recommended Dechlorinating Agent

Again, this is not necessary but it just makes it convenient.

There are some other ways to dechlorinate the water.
For example, storing the water in a bucket for or a night.

There are also various chemicals available to reduce the ammonia in the aquarium which comes in handy during an emergency.

6. Tank Size Matters

Tank size is very important in aquariums. As I have mentioned above, at least 10 to 20-gallon tank is good for beginners.

Don’t go below 10-gallon tank or a fishbowl.

Small tanks are actually difficult to maintain than the big tanks.

Because water chemistry changes very fast in small tanks which can cause problems for your fish.

For example, the ammonia level can increase very quickly in a small tank.

Also, the oxygen level decreases very fast in a small tank.

A bigger tank is more forgiving. And it will provide you sufficient time to make any arrangement to fix the problem.

Also, fish requires a sufficient amount of space for its proper growth or else it will get stunted i.e. it will not grow to its full potential.

7. Cycle The Tank

Your aquarium needs to go through a nitrogen cycle so that the beneficial bacteria will form in your aquarium.

This bacteria will help to reduce the ammonia which will be produced by your fish.

The mistake most beginners make is that they immediately introduce their fish into the tank without cycling it which causes the death of the fish.

So, before introducing the fish into the tank you need to wait for at least one month to complete the nitrogen cycle and form all the beneficial bacteria in the tank.

Now for sometimes it will require only 3 weeks to form beneficial bacteria and sometimes it will take even two months to form beneficial bacteria.

So, there is not the same time period for all tanks because it really depends on various factors.

The best way to test if your aquarium has beneficial bacteria or not is by using a test kit.

Check out our recommended Test Kit

8. The Place for Your Fish Tank

Before buying your aquarium you should decide where you want to put it in your home.

There are a few things you need to know before you decide where you should put your fish tank.

  • You should put your fish tank in the room where you usually sit and relax so that you can see your fish tank and enjoy it.
  • You have to maintain a constant temperature in your aquarium so make sure that there are no heating vents or fireplaces or hair conditioning units or vents near the place where you are going to put your aquarium.
  • Also, ensure that there is no noise source like speakers near the aquarium.
  • Don’t put your aquarium near the window where it will get exposed to the sunlight directly.
  • Also, don’t keep the aquarium in the room where there is a lot of sunlight.

9. Feeding The “Right Way”

Depending on the fish, you will need to feed it the food which is specifically made for it.

For example, Goldfish food contains high carbohydrates and low protein and generic fish food has high protein and low carbohydrate.

That’s why using any generic fish food for Goldfish is not a good idea.

In the same way, you should look if there is any specific food for your fish and feed it that food.

Also, before feeding your fish you should pre-soak the food into some water. 

Because if you feed them the food right away it can dry there swim bladder which can even cause death.

So, just take a plastic cup, add some aquarium water in it, add fish food in it, let it soak for a while and then feed it to your fish.

10. Overfeeding Can Be Fatal

Fish always look hungry and they will always entice you to feed them.

But you should not feed your fish all the time.

Overfeeding can be very severe and it can even cause death.

Besides, when you feed your fish very often, the uneaten food settles down on the bottom of the tank which produces ammonia and decreases oxygen which is very harmful to your fish.

For most fish, you should feed once a day and it will be just fine.

But for herbivorous fish i.e. the fish that rely on vegetarian food will need to feed more often.

Keeping fast-growing live plants with these fish is a very good idea because they can nibble on it whenever they feel hungry.

You should feed the amount of food your fish can consume completely within 3 to 5 minutes.

If you think you are overfeeding your fish then underfeed!

Because in the natural habitat of fish, they don’t get food regularly so most fish can live without food for a long time and you can always feed them later.

11. The “Right Way” to Clean Aquarium Stuff

When it comes to cleaning your aquarium stuff like the filter, gravel, etc.

You just can’t clean it with normal water and put it back in your aquarium.

As mentioned before, filters and gravel provide a space for the growth of beneficial bacteria.

So you need to be careful when you clean them because you may risk losing all the beneficial bacteria.

So, while cleaning the aquarium filter,  you should clean it with your aquarium water. This will help to preserve beneficial bacteria.

You can clean the gravel with normal tap water and it won’t be any problem, but to be on the safer side you should clean the gravel with aquarium water.

If you are going to clean the gravel with normal tap water then make sure that it is dechlorinated.

12. You Have to Dechlorine the Tap Water

Chlorine is harmful to your fish. 

So, if you are going to use normal tap water for your aquarium then, first of all, you need to dechlorinate it before adding it into your aquarium.

You can dechlorinate the water by simply pouring down the water in a bucket that you have never used with any soap or detergent. 

If you are in doubt then buy a new bucket because you are going to need it often for the maintenance of your aquarium and use it just for the aquarium.

Once you pour the water into the bucket then let it sit for at least 12 hours.

This will dechlorinate the water.

You can also use a dechlorinating agent to dechlorinate the water fast.

13. Maintain the Optimum Level of Oxygen in the Tank

Like us, fish also require a sufficient amount of oxygen to survive.

Maintaining an optimum level of oxygen is one of the most important things for a happy and healthy aquarium.

If the fish tank doesn’t have a sufficient amount of oxygen then the fish will suffocate and it can cause various respiratory disorders in your fish.

There are various signs that can tell you if your fish tank has low oxygen levels 

  • If your fish is coming on the surface gasping for air frequently
  • If you noticed rapid Gill movement in your fish etc.

The best the simplest way to oxygenate a fish tank is by using an air pump.

Besides, there are some other ways to oxygenate the fish tank.

14. Maintain the Ideal Temperature in your Fish Tank

Just like oxygen, fish also require an optimum temperature for their proper growth.

For example, Goldfish require 62 to 75 degree Fahrenheit temperature for its growth.

Some Fancy Goldfish are sensitive to the temperature below 62 degrees Fahrenheit and temperature above 75 degrees Fahrenheit can cause nerve damage in all Goldfish.

And most tropical fish need temperatures between 75°F and 80°F, or 24°C-27°C.

Like Goldfish and tropical fish, most fish require an optimum temperature for their proper growth and a higher or lower temperature than that can cause problems.

So, you should know the ideal temperature for your fish.

A heater can help you to maintain a constant temperature if you live in a cold region and your fish requires warm water.

Make sure that your aquarium is not near a window so that it is not directly exposed to the sunlight because it can raise the temperature inside the aquarium.

Also, make sure that there are no heating or cooling sources near the aquarium.

15. Ammonia is Deadly for the Fish

Ammonia is very harmful to your fish and it can cause the death of your fish.

Ideally, your tank should not contain any ammonia but if your tank contains ammonia more than 0.2 mg then it is very harmful to your fish.

The best way to keep track of ammonia is by using an ammonia tracking stripe.

If you noticed high ammonia then you should do a partial water change to reduce the ammonia.

As beneficial bacteria help to reduce ammonia in the water and filters provide a space for the growth of beneficial bacteria you should see if the water is coming freely from your filter or not.

If the water is not coming freely then your filter is most likely clogged. 

So, in this case, you should clean the filter using best practices. This will also help to reduce ammonia.

Another cause of high ammonia in your tank could be overstocking.

So, in this case, you should upgrade to a bigger tank.

Also, uneaten food can cause ammonia so if you noticed uneaten food on the surface or on the substrate of your tank then you should remove it using a fishnet or using a siphon.

Also, you should cut down on feeding to prevent a rise in ammonia in the future.


So as you can see there is a lot goes into maintaining a healthy fish tank. It may seem like very overwhelming.

But honestly, it is not that difficult, if you just do some research about your fish and follow best practices while setting up and cleaning the aquarium.

Photo of author
Prathmesh Gawai
He is the main author and editor at Aquagoodness.com. And he loves to share helpful information on aquarium and/or fishkeeping hobby. Prathmesh has over five years of aquarium and/or fishkeeping experience. Currently, he has a Betta fish tank. He has written hundreds of articles on various aquarium fish species and on fish tank maintenance over the last five years. Connect with him on YouTube here. Learn more about him here.

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