Setting up a freshwater tank requires six categories of supplies: the tank, filtration, a heater, lighting, substrate, and water treatment products. You can get a functional 20-gallon community setup running for about $150, or a well-appointed planted tank for $400 to $600. The list is shorter than most beginners expect, and knowing which items are genuinely essential versus marketing upsells will save you real money.
This guide walks through every supply category for a freshwater tank, with specific products at multiple price points, sizing guidance, and an honest take on what's optional for most setups.
The Tank
Tank size determines almost everything downstream, from filter sizing to stocking levels to water chemistry stability. Bigger tanks are actually easier to maintain because they dilute waste and temperature changes more gradually. A 20-gallon long (30 x 12 x 12 inches) is the most recommended starter size for good reason.
Budget option: The Aqueon 20-gallon long aquarium (bare tank) runs $35 to $55. It's made from standard glass with silicone seams and holds up well for years.
Kit option: The Marineland Penguin Power Filter Kit includes a 20-gallon tank, a Marineland Penguin 150 HOB filter, and a fluorescent hood for around $90 to $110. The filter included is genuinely adequate. The light is basic but works for fish-only setups.
Premium option: The Fluval Flex 32.5 gallons at around $200 includes a curved front glass panel, built-in filtration, and a multi-color LED. It looks significantly more polished than a standard rectangular tank.
One thing to keep in mind: buying a tank kit doesn't mean the included filter and light are the best choices for your specific fish and plants. They're often undersized. See filtration and lighting below for what to look for.
Filtration
A filter is the single most important supply decision after the tank itself. It houses the beneficial bacterial colonies that convert toxic ammonia (from fish waste and uneaten food) into less harmful nitrate through the nitrogen cycle.
For 10 to 30-Gallon Tanks
The AquaClear 50 Power Filter ($45 to $55) is the most recommended HOB filter in this size range. Its open media basket lets you customize what goes inside: foam for mechanical filtration, Seachem Matrix or ceramic rings for biological filtration, and activated carbon for chemical polishing. The adjustable flow rate is useful for slow-moving species like bettas.
The Seachem Tidal 35 or Tidal 55 ($50 to $70) is a newer alternative with a built-in surface skimmer that reduces surface film, which is beneficial in planted setups where surface agitation can gas off CO2.
For 40 to 75-Gallon Tanks
A canister filter outperforms HOB models at larger sizes because it has significantly more media volume for biological filtration. The Fluval 307 ($150) handles up to 70 gallons and is one of the most common canisters in the hobby. The Eheim Classic 350 at $120 is a quieter alternative with a proven track record.
For Nano Tanks Under 10 Gallons or Shrimp Tanks
A sponge filter powered by an air pump is the best choice. The Aquarium Co-Op nano sponge filter ($8 to $10) paired with a Tetra Whisper 40 air pump ($10 to $15) provides excellent biological filtration with no risk of trapping small fish, fry, or shrimp. This is also the cheapest and most low-maintenance filtration option available.
Heating
Most tropical freshwater fish need 74 to 80°F water temperature. A heater is essential unless you live somewhere warm enough that your room temperature never drops below 74°F year-round.
Reliable budget pick: The Aqueon Pro adjustable heater ($22 to $30 for the 100-watt version) includes an automatic safety shutoff if it's accidentally exposed to air. It's appropriate for 20 to 30-gallon tanks.
Best accuracy: The Eheim Jager TruTemp heater ($30 to $40 for the 100-watt version) has a calibration dial on top that lets you verify and adjust its temperature offset. This matters because many aquarium heaters run a few degrees high or low from their set temperature. The Jager is fully submersible and more reliable than most budget heaters.
Sizing rule: use 3 to 5 watts per gallon. A 55-gallon tank needs a 165 to 275-watt heater. Using two smaller heaters on large tanks (for example, two 150-watt units) provides redundancy so a single heater failure doesn't roast the whole tank.
Always use a separate digital thermometer rather than relying on the heater's temperature indicator. The Zacro Digital Aquarium Thermometer at $6 to $8 provides a continuous display and is accurate to within 0.1°C.
Lighting
Lighting requirements depend entirely on whether you're keeping a fish-only tank or a planted tank.
Fish-Only Tanks
Any basic LED aquarium hood is sufficient. The Nicrew ClassicLED Gen 2 ($25 to $35 depending on size) is a popular standalone LED that provides clean white light appropriate for displaying fish coloration without driving algae growth. It mounts on tank rims with adjustable brackets.
The key for any light is using a timer. Fish and plants need a consistent photoperiod, ideally 8 to 10 hours of light per day. A $8 to $10 mechanical outlet timer is all you need.
Planted Tanks
For low to medium-light plants (anubias, java fern, crypts, val), the Fluval AquaSky LED 2.0 ($80 to $110 depending on size) provides adequate intensity with a color temperature that works well for plant growth.
For medium to high-light planted tanks with fast-growing stem plants or carpeting plants, the Fluval Plant 3.0 LED ($150 to $180) or the Twinstar LED S series ($180 to $220) provide programmable spectrum and intensity suitable for most freshwater plants. The Fluval 3.0 app lets you program sunrise/sunset ramps and storm effects.
Substrate
The substrate you choose affects tank aesthetics, fish behavior, and plant health.
For community fish tanks: Natural pea gravel or aquarium gravel in 2 to 4mm size works for most fish. Carib Sea Super Naturals substrate at $15 to $20 for a 20-pound bag provides a natural sandy appearance. For bottom-dwellers like corydoras, fine sand (play sand or pool filter sand, $8 for a 50-pound bag) is better for their health since they sift through substrate constantly.
For planted tanks: An active substrate like Fluval Stratum ($20 to $25 for 4.4 pounds) or ADA Amazonia ($35 to $45 per bag) buffers pH slightly acidic and releases nutrients that plants absorb through their roots. These make a significant difference for heavy root-feeders like crypts, amazon swords, and stem plants.
For a 20-gallon long at a 2-inch depth, you need approximately 15 to 20 pounds of substrate.
Water Treatment Supplies
This category has the highest potential for expensive but unnecessary purchases. You need very few products done right.
Dechlorinator: Seachem Prime ($15 to $20 for 500mL) is all you need. It neutralizes chlorine and chloramine in tap water and temporarily detoxifies ammonia and nitrite. Use it every water change and whenever there's a chemistry emergency. A 500mL bottle treats 5,000 gallons of water.
Beneficial bacteria for cycling: Fritz Turbo Start 700 ($15 to $20 for 4 ounces) is the most effective bottled bacteria product available and can accelerate the nitrogen cycle to as few as 3 to 5 days with a proper fishless cycle. Add ammonia to 2 to 4 ppm (Dr. Tim's pure ammonia works well), dose Fritz, and test daily until ammonia and nitrite both reach zero.
Test kit: The API Freshwater Master Test Kit ($25 to $35) tests ammonia, nitrite, nitrate, and pH using liquid reagents that are significantly more accurate than test strips. Test daily during cycling, then weekly in an established tank.
For planted tanks only: A liquid fertilizer like Seachem Flourish Comprehensive ($12 for 500mL) covers micronutrients. For tanks with moderate to heavy plant loads, adding a nitrogen source like Seachem Flourish Nitrogen ($12) is worth it. CO2 injection (if you go that route) is a bigger topic, but the Fluval Mini Pressurized CO2 Kit at $35 to $45 is a good entry-level option for nano planted tanks.
For more detailed equipment comparisons, our Best Aquarium Equipment guide covers the top choices across all categories with head-to-head analysis.
Maintenance Supplies
Gravel vacuum: The Python No Spill Clean and Fill ($35 to $45) connects to a kitchen or bathroom faucet and makes water changes much less of a chore. For small tanks or if a faucet connection isn't available, a basic siphon vacuum ($7 to $10) works fine.
Algae scraper: The Mag-Float 125 magnetic cleaner ($18 to $22) lets you scrub algae off the inside glass without getting your hand wet. A simple plastic scraper blade ($5 to $8) handles more stubborn spots.
Buckets: Two 5-gallon buckets dedicated to aquarium use only. Label them clearly. Hardware store buckets at $6 each work perfectly.
Nets: A 6-inch net for catching fish ($4 to $6). Nothing fancy needed.
FAQ
What supplies do I need before adding fish to a new freshwater tank?
At minimum: a cycled filter with established bacteria (ammonia and nitrite testing at zero), a working heater, dechlorinator added to the water, and a test kit to verify chemistry. Don't skip the cycling step. Adding fish to an uncycled tank causes ammonia poisoning that kills fish within days.
Do I need CO2 injection for a planted freshwater tank?
No. Low-tech planted tanks using plants like anubias, java fern, crypts, and val grow well without CO2 if you keep lighting moderate (8 hours per day) and fertilize with Seachem Flourish. CO2 injection becomes worthwhile if you want fast-growing stem plants, carpeting plants, or are chasing competition-level aquascapes.
How much substrate do I need for a 20-gallon tank?
For a standard 2-inch substrate depth in a 20-gallon long (30 x 12 inches), you need approximately 15 to 20 pounds of gravel or 18 to 22 pounds of sand or aqua soil. Most substrate bags list a coverage guide on the label.
Can I put a freshwater tank anywhere in my house?
The tank should sit away from direct sunlight (causes algae blooms and temperature swings), away from heating/cooling vents, and on a level, stable surface that can support the weight. A 20-gallon filled with water and substrate weighs roughly 200 to 230 pounds including the stand, so verify that the floor and furniture can handle it.
Wrapping Up
Fresh water tank supplies are more straightforward than they might appear at first. A quality filter, reliable heater, accurate test kit, and Seachem Prime as a dechlorinator form the real core of a healthy tank. The rest depends on your specific fish species, whether you're doing a planted tank, and your aesthetic preferences. Buy what you need for your actual setup, skip the unnecessary add-ons, and invest the savings in water quality testing and maintenance habits. Our Top Aquarium Equipment guide has side-by-side comparisons of specific filters, heaters, and lights if you want to drill into any category further.