How Much Electricity Does a Fish Tank Use? – Average Cost

How Much Electricity Does a Fish Tank Use

One issue bugging many beginner aquarium hobbyists relates to how much electricity does a fish tank use. A 63-watt fish tank consumes about 1,500 watts daily, translating to a yearly electric consumption of about 550 kilowatt-hours.

The table below describes a fish tank cost in electricity and USD pegged at 16.8 cents per kilowatt-hour.


Fish Tank Electric Consumption in kWh

Average Electrical Cost in USD at $0.168/kWh










Of course, the figures might be different from your aquarium setup and where you live. Several factors can impact how much electricity does an aquarium use.

So, relax and continue reading to learn how to determine your fish tank’s electric consumption.

Fish Tank Electric Consumption and Aquarium Capacity


Some beginner aquarists are concerned fish tanks use a lot of electricity. With rising power costs, they have all the right to worry. After all, nobody wants to add several dollars to their monthly electric bill when they could earmark the money for more essential items.

The good news is that fish tanks do not consume too much electricity. They are not power-hungry appliances, unlike water heaters and ovens. However, the bigger the fish tank, the higher the likelihood of consuming more electricity.

For example, a 10 gallon fish tank with 72-degree Fahrenheit water only consumes about 150,000 watt-hours (or 150 kilowatt-hours) yearly.

How about a bigger aquarium? Can you guess how many watts does a 20 gallon fish tank use? You might think a 20-gallon aquarium consumes twice a 10-gallon unit’s electric consumption. You will be wrong because it only uses about 262.5 kWh annually.

How much electric current does a 55 gallon fish tank use? That would be around 799,000 watt-hours or 799 kWh annually.

We can deduce from these figures that a 5 gallon fish tank will consume less electricity than a 10- or 20-gallon aquarium.

The following table summarizes the average annual electric consumption of various aquarium sizes.

Aquarium Capacity in Gallons

Approximate Yearly Electrical Consumption in kWh

Estimated Annual Electricity Cost in USD at $0.168/kWh 
















We understand that bigger aquariums consume more electricity than smaller units. But why?

Fish Tank Equipment: the Driving Forces Behind an Aquarium’s Electric Consumption

Although aquariums are containers for water, fish, and other accessories, they require equipment to ensure the ideal environment for aquarium inhabitants. Unfortunately, these devices run on electricity.

1. Aquarium lighting


Aquariums have different lighting recommendations. For instance, a fish-only (no plants) aquarium setup requires one to two watts of illumination for every gallon. Hence, a 50-gallon fish-only tank needs 50 to 100 watts of lighting.

On the other hand, planted tanks need more light to promote photosynthesis. The watts per gallon planted tank calculator recommends two to five watts per gallon. Our 50-gallon example will need 100 to 250 watts of illumination.

Meanwhile, reef aquariums have higher illumination requirements – about four to eight watts a gallon. Hence, a 70-gallon reef tank uses about 280 to 560 watts of lighting.

You might also consider the fish tank illumination type. Fluorescent bulbs only consume 15 to 40 watts, while compact lighting fixtures use 300 to 100 watts. Meanwhile, VHO fluorescent bulbs draw 75 to 160 watts.

On the other hand, LEDs consume 80% less energy than conventional aquarium lighting (fluorescent bulbs).

Electric consumption also depends on how long you must leave the aquarium lights on. For instance, a 200-watt fish tank lighting running for 12 hours will consume 2400 watt-hours or 2.4 kWh.

2. Fish tank heating


Newbie aquarists might also like to know if fish tank heaters raise electric bill. They do.

Determining how many watts per gallon heater units consume is not as straightforward as some folks imagine.

For instance, tropical fish thrive best in a warmer environment (between 75 and 80 degrees Fahrenheit) than cold-water species (below 68 degrees Fahrenheit).

Experts recommend allotting 2.5 to five watts of heating for every gallon. You can expect to consume at least 137.5 watts for a 55 gallon tank (55 gallons x 2.5 watts = 137.5 watts).

While the guideline is straightforward, it does not account for temperature rise or the degrees you must elevate the water temperature from baseline.

For instance, the ambient room temperature is 69 degrees Fahrenheit, and your fish need 78 degrees Fahrenheit. The required temperature rise is nine degrees (78 degrees minus 69 degrees). You can multiply this temperature rise by the tank gallons, then divide the result by 2 to get the heater watts.

Using the table below, we need a 200-watt heater for a 40-gallon aquarium or a 25-watt heater for a 5-gallon tank, since aquarium products may not have the exact wattage in the table.

Fish Tank Size (in Gallons)

9-degree Fahrenheit Temperature Rise (in watts)

18-degree Fahrenheit Temperature Rise (in watts)



















3. Other aquarium equipment


Aquarium lights and heaters are not the only devices that use electricity. Filters, powerheads, water pumps, and air pumps also draw electricity.

Are you wondering how many watts does a water pump use? Pump wattage depends on the water flow rate, with 200-gallon-per-hour (GPH) units running on ten watts and 300 GPH pumps requiring 30 watts. I recommend checking your unit to be sure.

Filter, powerhead, and air pump wattage can range from 11 watts to up to 180 watts in total. Powerheads typically use 2.6 to 60 watts, while filters average 5 to 120 watts.

How to Calculate Electric Consumption and Convert to Cost


Calculating an aquarium’s electric consumption is an uncomplicated process. You only need to determine the fish tank device’s power consumption (in watts) and hours used before multiplying the product by your city’s energy rate.

For example, suppose you have a small fish tank with filter and light (no heater). Let us say the aquarium light uses 15 watts for 12 hours, and the filter uses 5 watts for 24 hours.

Our formula dictates multiplying wattage by hours used to determine the power consumption of each device.

  • Aquarium light = 15 watts x 12 hours = 180 Wh
  • Filter = 5 watts x 24 hours = 120 Wh

Combining the two, we get 300 Wh daily, 9,000 Wh (9 kWh) monthly, or 109.5 kWh annually.

Suppose you live in New York, where electricity costs 24.3 cents per kWh as of January 2023.

  • Daily = 0.3 kWh x $0.243 = $0.0729
  • Monthly = 9 kWh x $0.243 = $2.187
  • Yearly = 109.5 kWh x $0.243 = $26.6085

You can always use a fish tank electricity cost calculator if you do not like going through these calculations.

Tips to Save Electricity


How much electricity does a small fish tank use? It is lower than a big aquarium. Consider the following tips if you are concerned about your fish tank-related electrical expenses.

  • Use energy-efficient aquarium lighting fixtures (i.e., LEDs) or bulbs with lower wattage ratings.
  • Reduce the temperature rise between the original and target water temperature to save electricity. Go for the fish’s lower water temperature limit.
  • Pick water pumps and filters with lower flow rates (GPH).
  • Be diligent in comparing aquarium items before buying, and get only energy-efficient ones.
  • Consider reducing the aquarium device’s daily runtimes. For example, you can keep the fish tank lights on for ten hours instead of 12.
  • Opt for a fish-only aquarium setup to save on lighting.
  • Choose coldwater fish if you live in cold climates and tropical varieties if you live in warmer regions.


The answer to the question of how much electricity does a fish tank use varies according to the aquarium setup, including associated devices. As a rule, the bigger the fish tank is, the higher the electric consumption.

Fish tank lighting can consume one to eight watts per gallon, running between eight and twelve hours daily. Meanwhile, heaters use 2.5 to five watts a gallon. Filters, powerheads, air pumps, and water pumps also consume electricity that can add to the aquarist’s annual electric bill.

Aquariums without these gadgets or having only one or two should be more economical.