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How Much Does It Cost To Run A Fish Tank Aquarium

It is frequently said that people sell fry to cover the cost of running their aquarium/s and that the hobby of fish keeping can be an expensive one so we thought (and may regret!) it would be a good idea to try and quantify this.

We will go over we we consider to be a standard tank with standard equipment as an example however have put together a calculator which you can find at the end of this article to work out what the cost of running your aquarium is (don’t blame me if it’s higher than expected!).


As we see it, a typical aquarium is a 240 litre 4 foot tank with a 300W heater and 2x standard T8 tubes and a Fluval 306 filter. This is as you would buy it from the local fish store and is all is required to get it up and running. There are of course other things to take in to consideration such as how long the lighting is on for, ambient room temperature (this affects how long the heater is on for) and other equipment you may add such as powerheads, extra filtration and the like.

So if we take the basic set up we have the following equipment:

  • Fluval 306 Filter – 15W
  • Power-Glo Fluorescent Aquarium T8 Light Tube – 40W
  • Aqua-Glo Fluorescent Aquarium T8 Light Tube – 40W
  • Fish Tank Heater – 300W

I have listed the wattage of the equipment in the above list, this is essential to working out the cost of running, all equipment manufacturers will state the wattage of their equipment so you will need to find this out before you can work out the cost of running your fish tank.

We now need to look at each piece of equipment and how long it is on for and therefore how much it costs to run (we will work out the annual cost):

Fluval 306 filter – 24 hours per day
(15 Watts × 24 hours/day × 365 days/year)  ÷  1000 = 131.4kWh

Light tubes x2 – 14 hours per day
(80 Watts × 14 hours/day × 365 days/year)  ÷  1000 = 408.8kWh

Heater – 24 hours per day (this is worst case scenario and will be very unlikely to be on for 24 hours per day)
(300 Watts × 24 hours/day × 365 days/year)  ÷  1000 = 2628kWh

So the total kilo Watt hours (kWh) to run our standard aquarium (worst case scenario) is 3168.2kWh

At the time of writing the cost of a kWh is around 12 pence so the cost of running the aquarium for a year is 0.12 x 3168.2 = £380.18 so roughly £1 per day

The above is just a guide, why not fill out the form below to see how much your aquarium costs to run.