How much does an aquarium cost per month? Electricity, food and consumables
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
A 100-litre tropical aquarium costs 10 to 25 € per month, electricity included. Heating is the biggest item (3 to 8 € depending on the season and the room), ahead of lighting, food and consumables. It’s one of the cheapest pets to keep — provided you know which items can spiral.
Contents · 5 sections
How much electricity does an aquarium really use?
Based on a kWh at 0.25 €, for a 100-litre tropical tank: the 100 W heater doesn’t run continuously — it operates 20 to 40 % of the time in a room at 19-20 °C, i.e. 1.50 to 3 € per month (double in a cold room in winter). The 15 W LED light on for 8 hours adds about 0.90 €. The 5 W filter, always on, about 0.90 €. Electricity total: 3.50 to 8 € per month — half that for an unheated coldwater tank.
How much do food and consumables cost?
- Food: 3 to 8 € per month for a reasonable population, detailed in our food budget.
- Water conditioner: about 1 € per month (a 10 € bottle lasts 6 months to a year).
- Tests: 1 to 2 € per month averaged out (a 25-35 € liquid kit lasts a year and a half).
- Filter media: 1 to 2 € per month averaged out in sponges and floss.
- Water: 40 litres of monthly changes ≈ 0.20 €, negligible from the tap.
Which items blow up the bill?
Three traps: an overstocked tank (rising food and treatment costs), powerful lighting for demanding plants with CO2 (bottles or refills: 5 to 15 € per month), and reverse-osmosis water bought at the pet shop (0.30 to 0.60 € per litre, quickly 10 € per month). Conversely, a well-designed low-tech tank drops below 8 € a month all in.
How can you cut the bill without harming the fish?
Insulate the tank (back and sides against a cold wall: a 5 € polystyrene sheet), cover it to limit evaporation and heat loss, light it 7 to 8 hours instead of 12, and choose species compatible with the room’s temperature. Each degree of heating saved is worth roughly 10 % off that item. Our comparisons of economical equipment are in the accessories category.
Frequently asked questions
Does a 30-litre nano really cost less?
To run, yes: 5 to 10 € per month. But its instability causes more incidents; the saving is real mainly for unheated shrimp setups.
And a 240-litre tank — what monthly budget?
Allow 20 to 40 € per month: heating and lighting climb almost proportionally with volume, food follows the population.
Does an aquarium raise home insurance premiums?
Rarely below 300 litres, but declare it: an unreported water-damage claim may be poorly covered. A call to your insurer is enough.
In our shop, for this use: Programmable automatic aquarium fish feeder (€32.90) · the whole shop
This guide is part of Planète Pets’s Fishkeeping universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.