The real price of starting and keeping an aquarium
A basic aquarium setup costs between $200 and $500 for a small tank (20 gallons or less) with the essentials: the tank itself, a filter, a heater, substrate, and a few decorations. A medium setup (40 to 55 gallons) runs $400 to $800. Larger tanks or specialty systems—saltwater, planted, or heavily stocked—can easily exceed $1,000 to $2,000 before you add a single fish. The real ongoing cost, though, is what catches most people off guard: electricity, water treatments, food, and filter replacements add $20 to $50 per month for a small tank, more for larger ones.
The price varies wildly depending on what kind of fish you want to keep, how many, and how much you're willing to spend on equipment quality. A betta fish in a 5-gallon tank costs far less than a 75-gallon community tank or a saltwater reef setup. This guide breaks down where the money actually goes so you can decide what fits your budget and lifestyle.
Key Takeaways
- A small freshwater aquarium (20 gallons) costs $200 to $500 to set up, while medium tanks (40 to 55 gallons) run $400 to $800.
- Monthly operating costs—electricity, water treatments, food, and filter maintenance—typically range from $20 to $50 for small tanks and $40 to $100 for larger ones.
- Saltwater and specialty aquariums cost significantly more upfront and to maintain, often $1,500 to $3,000 or higher.
- The tank itself is usually the smallest expense; filters, heaters, lighting, and substrate make up the bulk of startup costs.
- Unexpected costs like fish illness, equipment failure, or water chemistry problems can add $100 to $500 in a single year.
What you actually pay for when you buy a tank
The tank itself—the glass or acrylic box—is often cheaper than people expect. A 20-gallon tank runs $30 to $80 new. A 55-gallon tank is $60 to $150. But nobody stops there. You need a filter ($40 to $150 depending on size and type), a heater ($25 to $60 for small tanks), and lighting ($30 to $100 if you want anything better than a basic hood). A stand to hold the tank costs $50 to $200. Substrate—gravel, sand, or soil—runs $15 to $40. Decorations, plants, and hiding spots add another $20 to $100.
For a 20-gallon freshwater setup, you're looking at roughly $250 to $400 in equipment before you buy a single fish. For a 55-gallon, add another $150 to $300. These are the one-time costs, but they're not truly one-time—filters wear out, heaters fail, and lighting degrades over years of use.
Monthly and yearly operating costs
Once the tank is running, you pay for electricity, water, and maintenance. A small tank (20 gallons) with a basic filter and heater uses roughly $5 to $15 per month in electricity, depending on your local rates and how often the heater runs. A larger tank (55 gallons) uses $10 to $25 per month. Water treatments—dechlorinator, pH buffers, beneficial bacteria—cost $5 to $15 per month if you're doing regular maintenance.
Fish food is cheap: $3 to $10 per month for most small tanks. The real recurring cost is filter maintenance. You'll replace filter media every 4 to 8 weeks at $5 to $15 per replacement, or $15 to $45 per month if you're being thorough. Add in occasional water testing supplies ($10 to $20 per month) and you're at $40 to $100 monthly for a medium-sized freshwater tank.
Over a year, that's $480 to $1,200 just to keep the water clean and the fish alive. Saltwater tanks run double or triple that because salt mix, calcium supplements, and more frequent testing are necessary.
Saltwater and specialty aquariums cost significantly more
A saltwater reef tank starts at $1,500 to $2,500 for a basic 40-gallon setup. You need a protein skimmer ($150 to $400), a chiller if your room gets warm ($200 to $600), specialized lighting for corals ($200 to $500), and live rock and sand ($200 to $400). Monthly costs run $60 to $150 because salt mix, calcium, alkalinity buffers, and test kits are expensive and used constantly.
Planted tanks with high-end lighting and CO2 injection systems cost $500 to $1,500 upfront and $30 to $80 per month to run. Aquascaping—the hobby of designing beautiful planted tanks—attracts people willing to spend $2,000 to $5,000 on a single setup.
If you're starting out, stick with a basic freshwater tank. Saltwater and specialty systems are rewarding but unforgiving if you miscalculate costs or lose interest.
Hidden costs that surprise new aquarists
Fish get sick. Medications, hospital tanks, and veterinary care (yes, fish vets exist) can cost $50 to $200 per incident. Equipment fails unexpectedly—a heater dies in winter, a filter motor burns out, a light ballast shorts. Budget $100 to $300 per year for replacements you didn't plan on.
If you travel or move, you'll pay for transport containers, temporary housing, or professional moving services for expensive fish or coral. A single high-end fish can cost $50 to $500, and losing one to poor transport is painful both emotionally and financially.
Water chemistry problems—algae blooms, ammonia spikes, pH crashes—sometimes require emergency water changes, new equipment, or professional consultation. These aren't routine costs, but they happen to most aquarists at least once.
How tank size affects total cost
| Tank Size | Startup Cost | Monthly Operating Cost | Annual Total (Year 1) |
|---|---|---|---|
| 5-gallon (betta) | $80–$150 | $10–$20 | $200–$390 |
| 20-gallon (small community) | $250–$400 | $30–$50 | $610–$1,000 |
| 55-gallon (medium community) | $400–$800 | $40–$80 | $880–$1,760 |
| 75-gallon (large community) | $600–$1,200 | $60–$100 | $1,320–$2,400 |
| 40-gallon saltwater reef | $1,500–$2,500 | $80–$150 | $2,460–$4,300 |
Larger tanks are actually more stable and cheaper to maintain per gallon than small ones—a 55-gallon tank is easier to keep balanced than a 10-gallon—but the absolute dollar amount is higher. If cost is your main concern, a 20-gallon freshwater tank offers the best balance of affordability and stability.
Ways to reduce aquarium costs
Buy used equipment. Tanks, stands, filters, and heaters from online marketplaces or local aquarium clubs are often 30 to 50 percent cheaper than new. Just inspect them carefully for cracks, rust, or motor damage before committing.
Start with hardy, inexpensive fish. Tetras, danios, corydoras catfish, and plecos cost $2 to $8 each and tolerate beginner mistakes. Avoid expensive or delicate species until you've kept fish for at least a year.
Do your own maintenance. Cleaning filters, changing water, and testing chemistry yourself costs almost nothing beyond supplies. Hiring someone to maintain your tank runs $50 to $150 per month.
Buy filter media and supplies in bulk. Many aquarists spend less per month by buying a year's worth of filter cartridges or water treatments at once, especially from online retailers.
Frequently Asked Questions
Is a 5-gallon tank cheaper to run than a 20-gallon?
Yes, upfront and monthly costs are lower for a 5-gallon tank, but it's harder to keep stable. Small tanks swing in temperature and chemistry faster, so fish get stressed more easily. A 20-gallon costs more but is more forgiving for beginners.
Do I need to spend $500 to start, or can I do it for less?
You can start with a 5-gallon betta tank for $80 to $150 and have a healthy fish. A 10-gallon setup runs $150 to $250. The $250 to $400 range is more comfortable because it gives you room for a filter, heater, and basic decorations without cutting corners on equipment quality.
What's the cheapest way to set up a saltwater tank?
There isn't one. Saltwater requires expensive equipment—skimmers, chillers, test kits—and specialty salt and supplements. The absolute minimum is around $1,200 to $1,500 for a 30-gallon setup, and you'll struggle with stability at that price. Budget $2,000 if you want a realistic chance of success.
How much does it cost to keep fish if I already have the tank?
For a 20-gallon freshwater tank, expect $30 to $50 per month in electricity, filter maintenance, water treatments, and food. For a 55-gallon, add $40 to $80 per month. Saltwater tanks run $80 to $150 per month.
Can I save money by not doing water changes?
No. Skipping water changes leads to ammonia and nitrate buildup, which stresses fish and causes disease. You'll end up spending more on medications and replacement fish than you would on water treatments and the time to do changes properly.