Aquarium store supplies span everything from life-support equipment to decorative gravel, and the quality difference between a good purchase and a bad one can mean the difference between thriving fish and a crashed tank. The most important supplies are a reliable filter, an accurate heater, a good water conditioner, and a proper test kit. Once those four categories are covered well, everything else is secondary.
This guide covers each major supply category you'll find in an aquarium store, what to look for, specific products worth buying, and which items you can safely skip or delay.
Filtration Supplies
Filtration is where your money matters most. A filter does the mechanical job of removing particles, the biological job of converting ammonia to nitrate via bacteria, and optionally the chemical job of removing discoloration and certain compounds via activated carbon.
Filter Units
The Aquaclear hang-on-back series is the most consistently recommended freshwater filter across experience levels. The Aquaclear 20 handles tanks up to 20 gallons, the 30 up to 30 gallons, and the 50 up to 50 gallons. What makes these stand out is the modular media design: foam sponge, activated carbon bag, and BioMax ceramic rings each occupy separate compartments and can be replaced independently. That means you can swap old carbon without disrupting the bacterial colony living on your foam and ceramic media.
Fluval canister filters, specifically the 207, 307, and 407, handle larger tanks and offer more biological filtration capacity with a lower maintenance frequency. Eheim canister filters, especially the Classic 250 and Classic 350, are simpler but proven over decades of use.
Filter Media
Replacement filter media from major brands is marked up significantly. Aquarium Co-Op's sponge media and ceramic rings work as well as branded alternatives at lower prices. Activated carbon should only be used when treating specific water discoloration problems, not permanently in the filter, since it stops working after about two weeks.
Seachem Purigen is worth keeping on hand for tanks with tannin-stained water from driftwood. Unlike activated carbon, it's rechargeable by soaking in bleach, then sodium thiosulfate, and works for months before needing regeneration.
Heating Equipment
Heaters
The Aqueon Pro Adjustable Heater and the Eheim Jager series are the two most reliable glass heater brands for freshwater tanks. Both regulate temperature accurately to within 0.5-1°F of the set point and include auto-shutoff features that prevent runaway heating.
For tanks with expensive or sensitive fish, titanium heaters like the Finnex HMA series are worth the premium. Titanium won't shatter from temperature changes or accidental impacts, and titanium heaters can be safely used with an external temperature controller like the Inkbird IBS-TH2, which adds an independent layer of temperature regulation.
Thermometers
Never trust a heater's built-in temperature readout as your sole monitoring. Digital probe thermometers like the ISTA Aquarium Thermometer read directly from the water and are accurate to within 0.5°F. Stick-on strip thermometers that attach to the outside glass read 2-3°F below actual water temperature. They're useful for a quick check but not reliable enough for sensitive species.
Water Chemistry Supplies
Water Conditioner
Seachem Prime is the best value water conditioner on the market. A 2oz bottle treats 500 gallons. A 500mL bottle treats about 25,000 gallons and costs around $15-20. It neutralizes chlorine, chloramine, and heavy metals, and temporarily binds ammonia and nitrite, making it useful during cycling crises as well as routine water changes.
API Stress Coat is a popular alternative with aloe vera for slime coat support. It works well but costs more per treated gallon than Prime. For most aquarists, Prime is the right choice; Stress Coat is worth adding when fish have been through shipping stress or physical damage.
Test Kits
The API Freshwater Master Test Kit is the standard liquid reagent test kit for freshwater tanks. It covers ammonia, nitrite, nitrate, and pH, which are the four parameters you need to monitor weekly in new tanks and after any fish losses or behavioral changes.
Test strips are less accurate than liquid tests and have a failure mode that's dangerous: they can read nitrite as zero when it's actually 0.25-0.5 ppm. At those levels, fish are in danger. The liquid test kit costs about $25 and lasts for hundreds of tests.
For reef tanks, the Salifert test kits for alkalinity, calcium, and magnesium are the standard. Hanna Instruments makes electronic colorimeters that test phosphate and nitrate with high accuracy and are worth the investment for serious reef keepers.
For a breakdown of where to source supplies most cost-effectively, the best aquarium supply store guide compares local and online options. For a broader look at the most important equipment purchases, the best aquarium equipment roundup covers filters, heaters, and lighting with specific product comparisons.
Substrate and Decorations
Substrate
Plain fine gravel in the 1-2mm range is the most versatile and easy-to-maintain substrate for community freshwater tanks. CaribSea Super Naturals line offers multiple color options in this grain size range, with the crystal river and torpedo beach variants being popular.
For planted tanks, Fluval Stratum volcanic substrate or CaribSea Eco-Complete provides root nutrients and maintains slightly acidic pH. ADA Amazonia is the premium option that serious planted tank keepers use. It produces ammonia when first set up, so new tanks with Amazonia need a longer fishless cycle.
For reef tanks and African cichlid setups, crushed coral or aragonite substrate buffers pH upward. CaribSea Arag-Alive substrates come pre-colonized with bacteria, which helps speed initial cycling.
Live vs. Artificial Plants and Decorations
Live plants are worth keeping even for beginners. Java fern, Anubias nana, and java moss require no special lighting or CO2 and absorb nitrates continuously. They provide shelter, reduce stress in fish, and make tanks look substantially more natural than plastic plants.
If you use artificial plants, silk plants are much safer than plastic. Plastic plants with rigid edges shred fish fins. Run pantyhose across any decoration before adding it to your tank; if the nylon snags, the decoration will damage your fish.
Food and Feeding Supplies
Quality fish food makes a visible difference in fish health and coloration. Omega One Freshwater Flakes, New Life Spectrum Community, and TetraMin Tropical Flakes are all solid everyday foods where real fish or whole ingredients are listed first.
For specialty fish, the food choices are more specific. Hikari Betta Bio-Gold for bettas. Hikari Sinking Wafers for plecos and corydoras. Omega One Veggie Rounds for herbivorous cichlids and snails. Frozen bloodworms as an occasional treat for virtually any fish that will accept them.
Invest in an automatic fish feeder like the Eheim Auto Feeder for vacation coverage. It dispenses precise quantities on a schedule and runs for months on standard batteries.
FAQ
What aquarium store supplies do I absolutely need for a new tank? A filter, a heater (for tropical fish), a thermometer, water conditioner, a test kit, a substrate, and appropriate food for your fish. Those basics cover tank safety and basic water quality management. Everything else is optional or species-specific.
How much does it cost to stock an aquarium with basic supplies? A functional 20-gallon freshwater setup with quality equipment runs $130-180. That includes an Aquaclear 30 or equivalent ($30-40), an Aqueon Pro 100W heater ($25-35), a basic LED light ($20-30), substrate ($15-20), thermometer ($5), water conditioner ($10-15), and a test kit ($25). Cheaper options exist at every category, but cutting corners on the filter and heater costs more in the long run.
Are brand-name aquarium supplies worth it over generic products? For equipment (filters, heaters, lights), yes. Established brands have better quality control, available replacement parts, and track records for reliability. For consumables like water conditioner and media, quality matters but generic alternatives often work as well. For decorations and substrate, brand matters less.
How often do I need to replace aquarium filter media? Activated carbon: every 2-4 weeks (or skip it entirely and use it only as needed). Foam sponge media: rinse in old tank water every 3-4 weeks, replace when it won't stay clean. Ceramic rings (bio-media): never unless physically falling apart; beneficial bacteria colonize these permanently. Replace only one type of media at a time to preserve your bacterial colony.