How Much Does It Cost to Run a 20 gallon Fish Tank?

It seems really awesome that now people can create an artificial marine environment in a glass tank. Interestingly, the process isn’t tricky today- all you need to do is spend some money on a regular basis. Afterward, observing the fish activities will be your great source of leisure time. Today, people are seen to build different sizes of fish tanks. The initial cost doesn’t cause much more headache to the buyer than the maintenance cost. 

So, how much does it cost to run a 20 gallon fish tank? Well, the total monthly cost to run a 20-gallon tank will be $4.87. We count electricity consumption of filter, heater, lighting, air pump, powerhead herein. Other costs like food, meditation, etc., will depend on your fish and the situation.

In the following section, we break down all the possible costs that may arise in your 20-gallon fish tank. 

Where do you need to spend? 

  1. Aquarium Lighting

Whatever the quantity of your fish tank is, the major consumption will occur in the aquarium lighting. But the one-time investment (light & hood cost) herein is less, roughly $30 to $40.

Typically, aquarium lighting accounts for roughly 45% of your monthly expenses. Interestingly, it is the only item that doesn’t demand full-time operation; instead,8 to 12 hours is ideal.

You have little chance to curtail the cost associated with lighting. Today, there are many energy-efficient lights found in the market. For example, you can consider the fluorescent light bulb, which works well in providing most hoods without adding significant cost. 

That type of light bulb’s watts typically lie in 15 to 40 watts. Also, you can use LED light because it will give you the same lighting at low watts compared to others. 

If your tank is planted, you need to ensure a higher lighting requirement, such as 30 to 100 watts. Alternatively, you can use VHO fluorescent bulbs (watts is 75 and 160) or use those two combinedly. 

If you have a reef tank, you need to provide higher watts, such as 150 to 100, which will increase the bill. 

2. Aquarium Heater

The monthly spending associated with the heater lies in the 2nd position on the maintenance cost list. But, the heater cost isn’t huge; instead, you need to spend around $15 or slightly higher.

However, the bill typically accounts for 35% of the total monthly bill. Running the heater is considered expensive. The cost usually depends on the tank size, which means the large size demands more heat. 

However, if you have tropical fish (Guppy, Catfish), you need to ensure a higher water temperature which will be expensive than non-tropical fish tanks. 

3. Other instruments

The next big cost will take place in the filtering section, which accounts for 12%. After that, the air pump and others will share 8% of the total monthly expenses. 

4. Food

The food cost for fish typically depends on the fish breeds. If you fill your fish tank with different varieties of fish, you have to spend on different types of food. 

For example, if you have tropical fish or goldfish, the food cost can be $10/monthly (approx.). That cost is also the same for bottom feeder disks or Plecostomus.

However, you may need to spend on some frozen bloodworms for the carnivores, then your spending will become approximately $6-$15/month.

5. Chemicals and Test Kit

You have to spend on chemicals like ammonia neutralizers, stabilizers, and water conditioners to keep the water healthy. Those chemicals can be brought individually or in a package. In this section, you may need to spend $50 to $80/yearly. 

Usually, the water quality can’t be detected until your fish show abnormal behavior. So, it is essential to monitor routinely using the test kit. Herein, your spending will lie between $15 to $50, depending on the tank size and test type. 

6. Filter Cartridges

You need a filter to remove debris and contaminations as well as neutralizing ammonia and nitrates. Moreover, the filter will help in growing healthy bacteria. The cartridge needs to change because it won’t run for a long time.

Typically, people use the external power filter, which will attach the tank’s backside. In the cartridges section, your spending will be $40-$55/ year.

7. Medication

You may notice some issues like red eyes or gills, open sores, bulging eyes, or bloated stomachs in your fish. To get rid of those problems, you can keep one or two bottles of medication handy. 

Here the cost will be $20-$30 per year. Note: If you wish to keep medication, try to keep a Stress Coat or Melafix or both. Those will work well against minor fish afflictions.

8. Decoration 

Indeed the funniest part for an aquarist is the tank’s decoration using driftwood, rocks, etc. Many items are available in the market to decorate a fish tank. If you want to manage a more natural approach, you can easily find it in the online or offline store. 

9. Plant Fertilizers

The live plant seems nice with a good lighting system. However, to make your live plant healthy and stay alive, you need to keep plant fertilizer handy. We suggest you buy API Leaf Zone and Seachem Flourish. 

Many users show their positive results after using it for a few days. This fertilizer comes in different size bottles, which may cost you $7 to $22. 

Note: You need a capful of plant fertilizer for your 20-gallon tank when a major water change occurs.

10. Automatic fish feeder

If you hang out for a couple of days or can’t provide food timely to your fish, then an automatic fish feeder will be a clever investment. The available automatic fish feeder may typically cost you $21 to $30. Interestingly, some automatic fish feeders offer compatibility with Alexa. 

Monthly Electric Cost Of 20 Gallon Tank:

This is the main segment that influences a person whether he/she buy an aquarium or not. 

In the following, we will visualize the approximate monthly cost of a 20-gallon tank. 

Items for a 20-gallon tank.

Heater75 watts (10 Degrees C)
Lights50 watts. (If you have coral or plants)
Filter10 watts (running on around 200 GPH)
Air pump2.5 watt

Let’s see the monthly calculation of power consumption.Let’s see the monthly calculation of power consumption.


The cost related to the heater will be:

If you run the heater 6 hours per day(75 watts*6 hours) 450 watts
The monthly consumption will become(450 watts*30) 13500 watts
After converting that figure into kilowatt13.5 kilowatts per month. Note: 1 kilowatt= 100 watts
If your per kilowatts cost is 12 centsTotal cost will be (13.5 kilowatts*12) $1.62 per month


Here is the cost associated with the lights:

If you use the light 10 hours a day(50 watts*10) 500 watts
The monthly consumption will become(500 watts*30) 15000 watts
After converting that figure into kilowatt15 kilowatts per month. Note: 1 kilowatt= 100 watts15 kilowatts per month. Note: 1 kilowatt= 100 watts
If your per kilowatts cost is 12 cents(15 kilowatts*12) $1.8 per month

Note: This cost is also applicable if you have a live plant or coral.


Here you can’t compromise because you need to run it 24 hours to keep the water clean. Then the cost will be:

If you use the filter the whole day(10 watts * 24 hours) 240 watts
The monthly consumption will become(240 watts*30) 7,200 watts
After converting that figure into kilowatt7.2 kilowatts per month. Note: 1 kilowatt= 100 watts
If your per kilowatts cost is 12 cents(7.2 kilowatts *12) 0.84 cents per month.

Air Pump

Like the filter, you need to run the air pump for 24 hours to ensure oxygen supply.

If you use the air pump the whole day(2.5 watts * 24 hours) 60 watts
The monthly consumption will become(60 watts*30) 1800 watts
After converting that figure into kilowatt1.8 kilowatts per month. Note: 1 kilowatt= 100 watts
If your per kilowatts cost is 12 cents(1.8 kilowatts *12) 0.22 cents per month.


This item also needs to run for 24 hours to ensure proper oxygen supply.

If you use the powerhead the whole day(4.5 watts *24) 108 watts
The monthly consumption will become(108 watts*30) 3240 watts.
After converting that figure into kilowatt3.24 kilowatts per month Note: 1 kilowatt= 100 watts
If your per kilowatts cost is 12 cents(3.24 kilowatts *12) 0.39 cents per month

Finally, we can see that the total monthly cost to maintain a 20-gallon tank will be $4.87 per month. At this cost, you can easily preserve coral or live plants in your fish tank setup. However, the yearly cost will be $58.44, hopefully, inexpensive for those with a small budget. 

Final Thoughts

Some people think the aquarium is a silent energy sucker, but today many energy-efficient devices make that statement false. We hopefully notified you of a clear idea of a 20-gallon fish water tank’s maintenance cost. The cost isn’t huge compared to its offered amenities. 

Notably, the cost may vary to the electricity cost and the product. We hope we can clarify all your questions related to how much does it cost to run a 20-gallon fish tank. 

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