best fish tank size for beginners

What Is The Best Fish Tank Size For Beginners

One of the first questions a novice aquarist has is:”What is the best fish tank size I should get?”
Does size matter?
Well, it actually impacts a lot more than you think.
There are many things to consider, like where will you put it in your home or office and what’s your budget?
You also need to consider how different sizes of fish tank impact the general water quality, the overall maintenance of the aquarium, and of course the fun part, stocking of the tank with fish.
Are you setting up an aquatic habitat in your home for your family or do you want to bring some colour and life to your office?
Let’s tackle these points one by one.

Size or Stocking: What Comes First?


If you purchase with size in mind first, then the species of fish will be determined according to the water volume that you will have available.
You will determine your stock options and habitat dwellers after you have decided on the amount of gallons your tank will be.
We recommend getting a bigger tank in the beginning

Anything under 10 gallons will require more water maintenance and will be more difficult to sustain, and actually not much worth setting up.

Try going with a 20 gallon or more if possible.

Read on for more explanations about why we recommend going big.

Keep in mind though that the bigger the tank, the more expensive the accessories, filters, and other supplies that you will need to keep your aquarium healthy and clean.
A clean and balanced aquarium means happy fish. Happy fish live longer and don’t need to be replaced as often.

If you want to learn more on 20 Gallon Fish Tanks check out this article.
Check also this article on 10 gallon starters kits if your room or budget does not allow a bigger fish tank.


On the other hand, if you have a list of fish for your initial stocking in mind then the size of the aquarium will be determined by this list.
There is a little bit of math involved when going this route.
The general and most common rule is that the tank must have as many gallons of water as it will have inches of fish.
Remember that this calculation needs to be planned with the full grown adult fish size in mind. This is a simple helpful calculation, but it is not unconditional.
There are resources that can help you do the math.
Again, remember that bigger is better.
If you follow what we just said, a 10-gallon tank can only hold a handful of medium sized aquatic fish.
Make sure not to overstock and consequently create an unhealthy environment for your fish.

One rule of thumb is:
when in doubt, understock.

It’s much easier to add more fish later than to deal with an overpopulated habitat, and this is a common mistake we often see in newbies.
You are so excited about getting started with your new aquarium and you want it so crowded of all the types of fishes that you end up with an environment that is more crowded than the subway during rush hours.
Luckily it does not take much to avoid errors like these with just a bit of good research and calculation.
Another misconception is that a fish can only grow as much as the tank can support.
Well, if a fish stops growing it is mostly due to being stunted and that is obviously not good who will not live a long and healthy life as it could.
The guys at suggest a 29 gallon tank to start with as a family hobby. Others recommend 55 gallon for for a starting tank.

In principle the bigger the better considering that the bigger the habitat, the more variety of fish and aquatic creatures you can comfortably put into it. This of course need to be taken with again of salt – we would not recommend a 75 gallon tank for a beginner as it brings along additional costs for the equipment that for a beginner would not be a wise choice.
If you want to keep bigger species like piranhas or big cichlids, you will need a minimum 40-gallon tank.

Once you are clear on the fish that you want to put into your tank, research the species and find out the adult size of each type and the compatibility with other fish that you want to add.
If you want to build a healthy community, you will need to research each fish carefully.
Make sure that they can cohabitate in a safe way. Some fish are very active, others not so much.
Some species are aggressive and others are shy.
It doesn’t take much to understand that putting incompatible fish in your tank will only raise stress levels inside the habitat and will also give you anxiety when seeing “bully” fish attack the timid ones.


The shape of your aquarium will also impact the types of fish you will chose.
The height and the length of the tank you prefer will influence your selection process.
Some species are bottom dwellers and others need more mid and top space.
Aquariums come in a variety of shapes, from rectangles to perfect round shaped spheres.

Where shall I put it?

When choosing the size that fits you best you need also to consider where you will place your tank in your home or office. The main points you need to carefully look into are:

  • Ambient Temperature

  • The Position of The Available Power Outlets

  • The Overall Safety of The Tank

Ambient Temperature

Remember that water temperature is affected by several factors including the temperature of the surroundings. You will want to put your tank in a place where the temperature doesn’t fluctuate too much.
Fish are extremely sensitive to water temperature changes and all depending on the types of fish that you have and the region where you live, you will probably need a water heater in your tank. If you want to learn more on aquarium heaters you can check out our post here.

Putting an aquarium near a window may seem like a visually good idea, but it is the absolute worst place to put it.

You will have a very difficult time keeping your water temperature stable if the aquarium is near a window or any other kind of open source. Also, direct sunlight will affect algae growth in a negative way.
Try to keep the tank as far away from any heating sources, vents or A/C.
Walk around your home or office and try to visualize the full tank in places that are both pleasant and atmospherically stable.

Take into consideration that the tank needs some space around it.
Don’t back it up against a wall or push it into a corner because you will then have a difficult time accessing the pump, lights, or any other maintenance tools that you need to get to on a regular basis.
So when choosing the size of your tank, don’t buy exactly the size that fits the spot, give the aquarium ample room to breathe.

Power Outlets

Your aquarium needs to be close to a power source because your filter, heater, and lights will need to be plugged in. You may use an extension cord if you find the perfect place in your home that happens to be a bit far from the outlets. Remember to tuck it away safely so that it doesn’t become a tripping hazard or even worse a tipping-over risk.

Overall Safety of The Tank

Next on your list of considerations is the safety and stability of the aquarium. Don’t put the tank in the middle of a high transit area. Try to find the place in your home or office that creates a safe environment for the inhabitants of your aquatic paradise. Depending on the size of the tank, the weight of the full aquarium needs to be considered.

A full set up tank is extremely heavy, so the placement decision is important in order to avoid having to move it at a later date.

Just doing a bit of math, if we consider a 70 gallons or up, the water weighs 3.78 pounds per gallon, plus the weight of the aquarium. If you consider that 90 gallon fish tanks are some of the most popular ones, also without the math you understand why weight is something to take into serious consideration when you place the tank in your home or office. Some guys advise to place bug aquarium in the basement and we fully agree with that.

The weight maters also when you choose a stand. We recommended to purchase an adequate aquarium stand for your tank. This will guarantee that the piece of furniture can support the weight of the full tank.
There are a range of different styles of aquarium stands, there is sure to be one to fit your decor. Select one that suits the total number of gallons of your chosen tank.

So with all this information regarding the location you should know where you will be putting the aquarium before heading out to the store and this will obviously have a decisive impact on the size and shape of the tank. Don’t get a tank that overpowers a room, it should flow and feel organic in the space. It should also not feel lost and scanty in the room.

What is My Budget?

The size of the tank is also strictly related with your budget.
The size of the tank will impact not only the cost of the tank itself but also the price of the filter, plants and fish that go into it.
Ready made starter kits are an excellent idea to get you up and started and can save you some money. You can always add more supplies later on.
There are a lot of interesting kits available on the market that you may contemplate when shopping for your first aquarium.
Check out this article if you are interested in all in one kits.
Aquarium keeping can be an expensive hobby, but so very rewarding. Once you get past the beginner’s hurdle, you will begin to feel more comfortable with growing your hobby bit by bit, fish by fish.

The Bigger the Better!

One of the most common questions among beginner is “If I get a large aquarium at the very start will it be too hard to manage?”

There is a popular saying in the aquarist world that goes:
“the bigger the better”.
It’s absolutely true within certain limits.

Purchase the biggest aquarium you can afford at the moment.
We seem to have a false thought process that says that we should start small, that we shouldn’t get in over our heads.
This is a normal reaction when taking up a new hobby.

Well, in the aquarist world things work differently. The opposite is actually true.

This misconception and natural inclination is not true because the aquarium requires regular work and maintenance no matter the size.
You will need to care for your aquarium and size has almost no impact on this fact.

The most important thing to have when keeping any type of aquatic habitat is healthy water.
Water needs to preserve a good balance of temperature, pH levels, and ammonia.
It is easier to keep these factors steady and healthy if the tank is bigger.

The smaller the tank, the more difficult to keep water chemistry and temperature stable because water quality degrades faster in a small tank and requires more water changes.

Water changes are best kept at a minimum because this can affect stress levels of your fish and disturb the temperature and chemistry of the water.
The system thrives when all factors are kept unchanging.

More water, more stability.


The aquarium keeping hobby is extremely satisfying when the start up concerns are dealt with in a smart way and when you are armed with all the necessary information to make the right decisions.
Remember that you are dealing with living creatures and keep in mind that you want to minimize possible injury or even death to your new pets.

Size is one of the most important question that you will need to consider right off the bat.
We can’t stress enough the fact that bigger is better.
Purchase the biggest aquarium that you can afford that will also fit comfortably in the designated area of your home or office.

Stick to your budget and remember that the ready made starter kits that are available are an excellent option.

If you decide to purchase with size in mind, stock accordingly afterwards.

If you have a stocking plan, research and calculate to make sure not to overstock.
When in doubt, under stock.

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