Aquarium costs break down into three parts: the tank itself, the equipment you need to set it up, and what you spend each month to keep it running
A basic glass aquarium tank costs between $50 and $200 depending on size. A 10-gallon tank runs $50 to $100. A 20-gallon tank runs $80 to $150. A 55-gallon tank runs $150 to $250. Larger tanks cost more, but the price per gallon drops as the tank gets bigger. Acrylic tanks cost more upfront than glass — sometimes twice as much — but they are lighter and less likely to crack if you move them.
Setup costs — the filter, heater, air pump, lighting, substrate, and decorations — typically run $200 to $500 for a small freshwater tank. A saltwater or reef setup costs significantly more because the equipment is more specialized. Once the tank is running, monthly costs for food, water treatments, and filter replacements average $20 to $50 for a small freshwater tank, and $50 to $150 for a saltwater tank.
Key Takeaways
- A basic 20-gallon freshwater tank with all equipment costs $300 to $400 to set up, not including the fish themselves.
- Glass tanks are cheaper upfront than acrylic, but acrylic is lighter and more durable if you plan to move the tank.
- Monthly maintenance costs $20 to $50 for freshwater and $50 to $150 for saltwater, depending on tank size and what lives in it.
- Saltwater and reef tanks cost two to three times more to set up and maintain than freshwater tanks of the same size.
- The largest cost after setup is usually replacing filter media and treating the water, not feeding the fish.
Tank size and material affect your starting price
Tank size is the first decision because it sets the price for everything else. A 5-gallon tank costs $30 to $60 and works for a single betta fish or a few small fish, but it requires more frequent water changes. A 10-gallon tank costs $50 to $100 and is the smallest size most people recommend for beginners because it is more stable — the water temperature and chemistry change more slowly. A 20-gallon tank costs $80 to $150 and gives you room for a small community of fish without constant maintenance.
Glass tanks are standard and cost less. Acrylic tanks weigh less and do not shatter, but they scratch easily and cost 50 to 100 percent more. A 20-gallon acrylic tank might cost $200 to $250 instead of $100 to $150 for glass. If you are setting up in a permanent spot and do not plan to move it, glass saves money. If you rent or think you might relocate, acrylic's durability may be worth the extra cost.
Equipment and setup costs for a functioning tank
You cannot fill a tank with water and add fish. The tank needs a filter, a heater (for most freshwater fish and all saltwater fish), lighting, and substrate. A basic hang-on-back filter costs $30 to $80. An air pump and air stone cost $20 to $40. A heater costs $20 to $50. LED lighting costs $30 to $100. Substrate — gravel, sand, or specialized media — costs $15 to $40 depending on how much you need and what type you choose.
Decorations and plants are optional but affect the total. Live plants cost $5 to $20 each. Plastic plants cost $2 to $10. Rocks and driftwood cost $10 to $50. A basic setup with no decorations runs $150 to $300. A setup with plants, rocks, and a nice background runs $250 to $500. Saltwater setups cost more because the filter must be more powerful, the heater more precise, and the lighting more intense. A basic saltwater setup runs $400 to $800 before you add any fish.
Monthly costs for food, water treatment, and maintenance
Fish food costs $5 to $15 per month for a small tank. Most fish eat once or twice a day, and a container of flakes or pellets lasts weeks. Water conditioner, which removes chlorine and heavy metals, costs $10 to $20 per month if you treat every water change. Beneficial bacteria supplements cost $10 to $30 per month if you use them regularly, though many people skip them after the tank is established.
Filter media replacement is the largest recurring cost. Depending on the filter type, you replace the media every two to four weeks. Replacement cartridges cost $5 to $15 each, so budget $10 to $30 per month. If you use a canister filter instead of a hang-on-back, you replace the media less often but spend more per replacement. Saltwater tanks need more frequent water changes and more additives — calcium, alkalinity buffers, and salt mix — which can run $50 to $100 per month.
Saltwater and reef tanks cost significantly more
Saltwater aquariums are more expensive at every stage. The tank itself costs the same, but the equipment is specialized. A saltwater filter must handle higher bioload and usually includes a protein skimmer, which costs $100 to $300 alone. The heater must be more precise because saltwater fish are sensitive to temperature swings. Lighting for a reef tank with corals costs $200 to $500 because corals need specific light wavelengths and intensity.
Monthly costs for saltwater are higher because you need marine salt mix ($20 to $40 per month), calcium and alkalinity supplements ($20 to $40 per month), and more frequent water changes. A 55-gallon saltwater tank costs $100 to $150 per month to maintain, compared to $30 to $50 for a freshwater tank of the same size. Reef tanks with corals cost even more because corals need specialized food and lighting adjustments.
What affects the total cost beyond tank and equipment
Fish themselves cost $5 to $50 each depending on the species. A hardy goldfish costs $5 to $10. A colorful cichlid costs $15 to $40. Rare or specialty fish cost $50 to $200 or more. If you want ten fish, that is $50 to $500 just for the animals. Some people spend more on fish than on the tank.
Unexpected costs happen. A heater breaks and needs replacement ($30 to $60). A fish gets sick and needs medication ($10 to $30). You decide you want better lighting or a larger filter and upgrade ($50 to $200). Budget an extra $100 to $200 in your first year for repairs and upgrades. After the first year, most people spend $30 to $100 per month on a small freshwater tank and $100 to $200 per month on a saltwater tank.
Comparing freshwater and saltwater costs at a glance
| Cost Category | Freshwater (20 gal) | Saltwater (20 gal) |
|---|---|---|
| Tank | $80–$150 | $80–$150 |
| Filter and air pump | $50–$120 | $150–$350 |
| Heater and lighting | $50–$150 | $100–$250 |
| Substrate and decor | $30–$80 | $40–$100 |
| Total setup | $210–$500 | $370–$850 |
| Monthly maintenance | $20–$50 | $80–$150 |
Frequently Asked Questions
Can I start an aquarium for under $100?
Yes, but only with a very small tank. A 5-gallon tank with basic equipment costs $80 to $120 total. You will need to do water changes more often because small tanks are less stable. A 10-gallon setup costs $150 to $200 and is more forgiving for a beginner.
Is it cheaper to buy a kit or buy the tank and equipment separately?
Kits usually cost the same or slightly more than buying pieces separately, but they save time because everything is matched and ready to go. If you shop sales and compare prices, buying separately can save 10 to 20 percent. Kits are better for beginners because you do not have to guess what size filter you need.
How much does it cost to replace a broken heater or filter?
A replacement heater costs $20 to $60 depending on wattage. A replacement filter costs $30 to $100. Keep $100 to $200 set aside in your first year for repairs. After that, budget $50 per year for unexpected replacements.
Do I need to spend more money if I want colorful fish?
Colorful freshwater fish like tetras and guppies cost $3 to $10 each, the same as plain fish. Colorful saltwater fish cost $20 to $100 each because they are harder to keep alive. The tank and equipment cost the same either way — the difference is in the fish themselves.
What is the cheapest way to get your free guide with an aquarium?
Buy a 10-gallon glass tank kit ($120 to $180), add a few hardy fish like guppies or tetras ($10 to $20), and do regular water changes. Avoid expensive decorations and specialty equipment. Your first-year cost will be $250 to $350, and monthly costs will be $20 to $30.