The actual cost of keeping a fish tank for a year

A 200-liter community tank costs $150-250 per year to run after the initial setup. Electricity is the biggest line item. Here's the full breakdown by tank size.

Nobody talks about the ongoing cost of a fish tank until you've already bought one. The setup cost (tank, stand, filter, heater, light, substrate, fish) gets all the attention. The monthly bills get ignored. Here's what it actually costs to keep a freshwater tank running for a year, broken down by category.

Electricity

The biggest ongoing cost. Three things use power: the heater, the filter, and the light.

Heater: A 200W heater in a 200-liter tropical tank in a climate-controlled house (20-22°C ambient) cycles on roughly 30-40% of the time to maintain 25°C. That's about 60-80W average draw, or 525-700 kWh/year. At $0.15/kWh (US average), that's $80-105/year. In a warm house or during summer, it cycles less. In a cold fishroom, it runs nearly continuously.

Filter: A canister filter draws 10-25W continuously. A HOB filter draws 5-15W. Running 24/7, that's 88-219 kWh/year, or $13-33/year.

Light: A 30W LED running 8 hours/day: 87 kWh/year, or about $13/year.

Total electricity for a 200-liter tank: roughly $100-150/year. The running cost calculator gives a more precise estimate based on your equipment wattages and local electricity rate.

Smaller tanks use less. A 60-liter tank with a 50W heater and a small HOB costs about $40-60/year in electricity. Larger tanks use more: a 400-liter tank with a 300W heater can hit $200+/year.

Food

Quality tropical fish flake or pellet food costs $8-15 per container. A 200-liter community tank with 20-30 small fish goes through about 2-3 containers per year. Budget $20-40/year for food.

Specialty diets (frozen bloodworms, brine shrimp, algae wafers for bottom feeders) add $20-30/year if you feed them regularly.

Water conditioner

A 500 ml bottle of dechlorinator (Seachem Prime, API Stress Coat) costs $10-15 and treats about 5,000 liters. With 25% weekly water changes on a 200-liter tank (50 liters per change, 2,600 liters per year), one bottle lasts roughly two years. Budget $5-8/year.

Filter media

Mechanical media (filter floss, sponge pads) needs replacement every 2-6 months. Biological media (ceramic rings, bio balls) lasts years and rarely needs replacing. Budget $15-25/year for mechanical media replacements.

Activated carbon, if you use it: $10-15/year. Most freshwater tanks don't need it on an ongoing basis.

Test kits

A liquid test kit (API Master Kit) costs $25-35 and lasts 1-2 years depending on how often you test. Budget $15-20/year. Test strips are cheaper per purchase ($10-15 per box) but less accurate and run out faster.

Replacement equipment

Things break or wear out. Heaters last 2-5 years. Filter impellers last 3-5 years. LED lights last 5+ years. Silicone on a glass tank lasts 10-15 years. Averaged over time, expect $20-40/year in replacement parts and equipment.

Plants and livestock replacements

Some fish die. Some plants don't make it. If you're adding new species or replacing losses, budget $20-50/year. In an established, stable tank, this drops close to zero. In the first year, it's higher because you're still stocking and figuring out what works.

Full annual cost by tank size

60-liter (15 gallon) community tank:

• Electricity: $40-60
• Food: $15-25
• Supplies (conditioner, media, tests): $20-30
• Replacements: $10-20
• Total: $85-135/year ($7-11/month)

200-liter (50 gallon) community tank:

• Electricity: $100-150
• Food: $25-40
• Supplies: $30-45
• Replacements: $20-40
• Total: $175-275/year ($15-23/month)

400-liter (100 gallon) planted tank:

• Electricity: $180-250
• Food: $35-50
• Supplies (including fertilizers): $50-80
• Replacements: $30-50
• CO2 refill (if injected): $30-50/year
• Total: $325-480/year ($27-40/month)

These numbers assume US electricity prices. In Europe, Australia, or other high-electricity markets, the heater cost roughly doubles.

What this doesn't include

Setup cost. The tank, stand, filter, heater, light, substrate, and initial livestock are one-time purchases that vary wildly ($100-300 for a basic 60-liter setup, $500-1,500 for a 200-liter planted tank, much more for large or premium setups).

Water. Municipal water used for changes costs pennies per week. Not worth tracking.

Your time. Weekly maintenance takes 20-30 minutes. What that's worth is between you and your hobbies.

Hidden costs that add up

Replacement fish. Fish die. Disease, aggression, old age, or mistakes take fish out of the tank over time. Restocking a community tank after losses costs $20-80 depending on species. Discus or specialty cichlids are obviously more expensive to replace than tetras.

Medication. A single disease outbreak can run $15-40 in treatments (Ich-X, Maracyn, Kanaplex, and the like). If you stock fish without quarantining, expect to treat the main tank once or twice a year.

Test kit refills. An API Master Test Kit lasts about 800 tests. Heavy testers (daily during cycling, weekly after) go through a kit in about a year ($25-30 to replace).

Substrate and hardscape replacement. Sand and gravel last indefinitely, but active aquasoil substrates for planted tanks exhaust their nutrient capacity and buffering after a year or two. Replacing substrate in a stocked tank is a significant project.

Upgraded equipment. Most fishkeepers upgrade something within the first year: a better filter, a more accurate heater, a timer for the light, a gravel vacuum, a better net. These incremental purchases add $50-150/year to the actual cost of the hobby.

Reducing costs without cutting corners

Buy consumables (filter media, dechlorinator, test kits) in bulk online rather than from local fish stores. A 500 mL bottle of Seachem Prime from an online retailer costs about the same as the 100 mL bottle at a brick-and-mortar store.

Use the water change calculator to optimize your change schedule; oversized water changes waste dechlorinator and salt mix, while undersized changes lead to problems that cost money to fix.

The first year vs ongoing years

Year one is always the most expensive because it includes tank, filter, heater, light, substrate, hardscape, and the initial fish purchase. A new 150-liter community tank fully set up costs $250-600 depending on equipment quality. After that, ongoing annual costs drop to $150-350 in consumables, electricity, and occasional replacements. The hobby pays back in relaxation and engagement what it costs in dollars, and a well-maintained tank lasts decades with only consumable costs to maintain.