The short answer
Running an aquarium is cheaper than most people expect. The ongoing cost is mostly electricity for the heater and light, plus a handful of consumables — food, dechlorinator, test reagents and the occasional bit of filter media. For a typical tropical tank it usually works out to a modest monthly figure, dominated by the heater.
Where the money actually goes
- Heater: the biggest running cost. It cycles to hold temperature, so a cold room or a large volume raises the bill. A cold water tank with no heater is much cheaper to run.
- Light: modern LEDs are efficient and run only 6–8 hours a day, so they cost little.
- Filter pump: runs 24/7 but draws only a few watts.
- Air pump: negligible.
The consumables
Beyond electricity you’ll steadily use fish food, dechlorinator for water changes, test kit reagents, and now and then replacement filter media or a new bulb. None are expensive individually, but they add up over a year — budget a little each month.
Keeping costs down
An efficient heater matched to your room, an LED light on a timer, and staying on top of maintenance so gear runs efficiently all trim the bill. A bigger tank costs more in absolute terms but is more stable and forgiving — see is a bigger aquarium easier to keep. Browse gear on our heater and filter hubs.