Main Aquarium Supplies

The main aquarium supplies you need are the tank itself, a filter, a heater (for tropical species), a light, water conditioner, a thermometer, and a test kit. That's the core list. Everything else, substrate, decorations, air pumps, CO2 systems, protein skimmers, is either specific to your setup type or genuinely optional depending on what you're keeping.

New hobbyists often get overwhelmed by the sheer number of products marketed as essential. Most of it isn't. The actual essential list is short. This guide breaks down the supplies you need, what to look for in each category, and what you can skip or add later as your tank matures.

The Tank

Your tank choice sets everything else. The size determines filter capacity, heater wattage, lighting footprint, and how many fish you can keep sustainably.

For most beginners, a 20-gallon tank (specifically the 20-gallon long at 30x12x12 inches) is the better starting point than the commonly marketed 5 or 10-gallon kits. Smaller tanks are harder to maintain because water chemistry fluctuates faster in smaller volumes. A small ammonia spike in 5 gallons crashes quickly; the same amount in 20 gallons is diluted and manageable.

That said, a 10-gallon tank is the standard entry point for a betta fish, which genuinely does well in smaller, calmer water. For community tropical fish, 20 gallons is the practical minimum.

Tank kits that bundle tank, filter, heater, and sometimes light together are worthwhile for beginners. Aqueon Starter kits and Marineland Portrait tanks include decent equipment that works well for months or years. The savings versus buying each component separately is real, usually $20 to $40.

Filtration

A filter is non-negotiable. It removes fish waste, uneaten food, and toxic ammonia through mechanical, chemical, and biological filtration.

The three main filter types for home aquariums are hang-on-back (HOB), canister, and sponge filters.

Hang-on-back filters clip to the back rim of the tank and are the standard choice for most freshwater setups under 75 gallons. The Aquaclear series (Aquaclear 20, 30, 50, 70) and the Seachem Tidal 35 and 55 are consistently recommended by hobbyists. These use replaceable or cleanable media and are easy to maintain.

Canister filters sit under the tank, pull water through tubing, and push it through a chamber of filtration media before returning it to the tank. They hold more media than HOBs and are better for larger tanks, planted tanks, and marine setups. The Fluval 207 (handles up to 45 gallons) and Fluval 307 (up to 70 gallons) are solid mid-range options. Eheim's Classic series is older in design but extremely reliable.

Sponge filters are used mainly in breeding setups and quarantine tanks where you want gentler flow. They're cheap, reliable, and run on an air pump. For a main display tank, they're typically supplemental rather than primary filtration.

Heating

Most tropical fish need water in the 75 to 82 degree Fahrenheit range. Room temperature alone rarely maintains this without fluctuation. A submersible heater handles it.

Size your heater at roughly 3 to 5 watts per gallon. A 20-gallon tank needs a 75 to 100-watt heater. A 50-gallon tank needs a 150 to 200-watt heater, or two smaller heaters for redundancy.

The Fluval E series digital heaters have an external temperature display and precise electronic control, which is worth the extra cost over basic glass heaters that tend to drift. The Eheim Jager is another reliable option with a calibration dial and auto-shutoff if the heater runs dry.

For cold-water fish (goldfish, white cloud minnows) or room-temperature setups in moderate climates, a heater may not be necessary.

Lighting

Light requirements vary enormously based on what you're keeping.

Fish-only freshwater: Any standard hood light or basic LED strip covers fish viewing. Fish don't need high-intensity light. The Aqueon LED hoods that come with starter kits are fine.

Planted tanks: Plants need appropriate light intensity and spectrum. For low-tech planted tanks with easy plants like java fern, anubias, and moss balls, a moderate LED like the Fluval Plant 3.0 or the Hygger Full Spectrum LED handles the spectrum and intensity. For high-tech CO2-injected planted tanks with demanding species, higher PAR fixtures are necessary.

Saltwater fish-only: Similar to freshwater fish-only for light requirements. Any decent LED covering the full tank footprint works.

Reef tanks: Coral requires specific light intensity and spectrum. This is where lighting cost increases significantly. AI Hydra and Radion models dominate the reef hobby for good reason. Don't use a basic freshwater LED on coral and expect good results.

For a full comparison of lighting and other key gear, the best aquarium equipment guide covers specifics across categories.

Water Conditioner and Dechlorinator

Tap water contains chlorine and chloramines that are toxic to fish. You need to neutralize these before water contacts fish.

Seachem Prime is the industry-standard recommendation and for good reason. It neutralizes chlorine, chloramines, and ammonia, and a 500mL bottle treats 5,000 gallons. A few drops per gallon on water changes covers everything. At roughly $15 for 500mL, this is one of the cheapest things you'll buy and one of the most important.

API Stress Coat is an alternative that adds aloe vera for slime coat repair, which some hobbyists prefer during transport stress or after aggressive tankmate incidents.

Test Kit

You need to monitor ammonia, nitrite, and nitrate, at minimum during the nitrogen cycle (the first four to eight weeks of a new tank) and periodically thereafter. PH testing is useful for planted tanks and sensitive species.

The API Freshwater Master Test Kit covers ammonia, nitrite, nitrate, and pH in liquid drop format with enough reagent for hundreds of tests. It costs $25 to $30 and is the most commonly recommended starting test kit.

For reef tanks, you'll also need tests for alkalinity, calcium, and magnesium. Salifert individual test kits are widely used in the reef hobby for precision. Red Sea's Pro test kit bundle covers all three reef parameters.

Thermometer

You need a way to verify water temperature independent of the heater's dial, which can drift.

A basic glass thermometer with a suction cup costs $2 to $4 and works perfectly. Digital stick-on thermometers are $5 to $8 and easier to read at a glance. The temperature accuracy of either type is sufficient for monitoring, though digital thermometers with external probes (like the Inkbird IBS-TH2) are more accurate if you want precision readings.

Substrate

Substrate is technically optional for a bare-bottom tank, but most setups benefit from gravel or sand for both appearance and beneficial bacteria colonization.

Freshwater: Plain gravel or aquarium sand works for most setups. For planted tanks, nutrient-rich substrate like Fluval Stratum or ADA Aquasoil provides the nutrients rooted plants need without fertilizer supplementation.

Saltwater: Live sand (sand with beneficial bacteria) establishes the biological filter faster in a new marine tank. Caribsea Special Grade Reef Sand is a common choice at $30 to $40 for a 20-pound bag.

What You Don't Need Right Away

Air pumps and airstones: Nice to have for additional oxygenation but not required if your filter creates surface agitation.

CO2 systems: Only for planted tanks with demanding plant species. A beginning planted tank with easy species doesn't need CO2.

Protein skimmers: Only for saltwater tanks, and even then, a lightly stocked fish-only saltwater tank can run without one for a while.

UV sterilizers: Optional equipment for tanks with disease history or high livestock density.

The top aquarium equipment breakdown covers the specialty gear worth adding as your tank matures and your goals become clearer.

FAQ

What's the minimum equipment list for a betta fish tank? A 5 to 10-gallon tank, a gentle filter (sponge filter or low-flow HOB), a heater, a basic LED light, water conditioner, and a thermometer. Bettas don't need powerful flow or high light. The Fluval Spec V (5 gallons) comes with a filter and light in a compact package that works well.

Do I need a protein skimmer for a freshwater tank? No. Protein skimmers are a saltwater technology that removes dissolved organic compounds from marine water. They have no application in freshwater tanks.

How often do I need to test my aquarium water? During the first month of a new tank (while it cycles), test every two to three days. Once the tank is established, monthly testing is typically sufficient unless something seems off (fish acting strangely, unusual odor, algae bloom). Reef tanks require more frequent testing, weekly or even every few days for alkalinity when running SPS corals.

Can I use a fish tank without a filter? Only in very specific scenarios: certain planted "walstad" setups rely on plant uptake to process waste, or low-density shrimp bowls with frequent water changes. For any setup with fish, a filter is effectively required for sustainable water quality. Without one, you'll be doing 50 percent water changes multiple times per week, which stresses fish more than a filter would.

The Simplified Starting List

Tank, filter, heater, light, conditioner, thermometer, test kit. That's genuinely all you need to set up a healthy freshwater tank. Add substrate and decorations for aesthetics and beneficial bacteria surface area. Everything else comes later as your goals develop. Getting those seven items right is worth more than buying twenty specialized products out of the gate.