Buying fish aquarium supplies online is almost always cheaper than buying from a local pet store, and the selection is dramatically wider. You can find specialty items that no brick-and-mortar store within 50 miles would stock, compare prices across retailers in seconds, and have everything delivered to your door. The main tradeoffs are shipping costs on heavy items, waiting for delivery when something breaks, and not being able to inspect products before buying.
This guide covers the best online retailers for aquarium supplies, how to decide what to buy online versus locally, what to watch for when shopping, and how to save money without sacrificing quality. Whether you're setting up your first tank or restocking a reef system, knowing where to look online makes a real difference in what you spend.
The Best Online Retailers for Aquarium Supplies
Not all online aquarium stores are equal. Price, selection, customer service, and livestock health guarantees vary significantly.
Amazon
Amazon is the default starting point for most hobbyists, and for good reason. The selection is enormous, prices are competitive, and Prime shipping means you can get most hard goods in two days. The downside is that product quality and authenticity can vary, especially for lower-cost items from third-party sellers. Stick to sold-by-Amazon listings or established brands when buying anything electrical.
Amazon works best for: filters, heaters, lighting, substrate, decorations, test kits, and chemicals.
Chewy
Chewy has become a strong competitor for aquarium supplies, particularly for food, medications, and standard equipment brands. Their customer service is genuinely excellent, and they have an auto-ship option that gives you 5 to 35 percent off on recurring orders. If you're buying fish food, filter media, or water conditioners monthly, auto-ship pays off quickly.
Chewy works best for: fish food, filter media, water conditioners, medications, and standard equipment from major brands.
That Fish Place / That Pet Place
One of the oldest and largest dedicated aquarium retailers online. Their selection of saltwater and reef equipment is particularly strong, and they frequently run sales that beat Amazon prices on specialty items. If you're looking for sumps, protein skimmers, or reef chemistry, this is a reliable source.
Bulk Reef Supply (BRS)
BRS is the go-to retailer for reef tank hobbyists. They stock a comprehensive range of equipment, chemicals, and dry rock, and their own-brand products like BRS Two-Part are well-regarded and priced fairly. BRS also produces an extensive library of free video content that helps you understand what you're buying and how to use it correctly.
Marine Depot
Another dedicated aquarium retailer with strong selection on reef and saltwater equipment. They run frequent promotions and carry brands that smaller stores don't stock. Their customer service team actually knows aquariums, which matters when you have a technical question.
Aquarium Co-Op
Run by well-known YouTube aquarist Cory McElroy, Aquarium Co-Op ships a curated selection of plants, medications, and equipment that Cory's team has personally tested and vetted. The selection is smaller than big retailers, but everything they stock is something they'd actually use. Their Easy Green fertilizer and Wonder Shell are popular with planted tank hobbyists.
What to Buy Online vs. Locally
The calculation is simple: buy online for anything standardized and non-urgent, buy locally for anything you need today or anything where inspection matters.
Buy Online
Filters, heaters, lighting, substrate, decorations, test kits, water conditioners, filter media, dry goods, and most chemicals ship well and are almost always cheaper online. A Fluval 407 canister filter costs $20 to $40 less on Amazon than at PetSmart most of the time.
For a comparison of oxygen-related equipment options, check out our guide on oxygen machines for fish tanks if you're shopping for air pumps and accessories.
Buy Locally
Live fish and corals are risky to ship, especially for beginners. Local fish stores give you the chance to see the fish, assess their health, and quarantine before adding them to your display tank. Live plants can ship well but local store stock is often healthier and cheaper once you factor in shipping.
Also buy locally when something breaks and you need it today. Heaters fail in winter. Filters stop working at the worst times. For emergencies, local store stock beats a two-day wait.
How to Compare Prices Effectively
Google Shopping
Searching "[product name] site:amazon.com OR site:chewy.com" in Google Shopping shows you real-time prices across major retailers. You can also use camelcamelcamel.com to see Amazon price history, which is useful for identifying when a price is genuinely on sale versus just listed with an inflated "was" price.
Watch for Hidden Shipping Costs
A filter listed at $89 with $12 shipping is $101. The same filter at $95 with free shipping is cheaper. Always add shipping before comparing. Most major retailers offer free shipping above a threshold, typically $49 to $75.
Buy in Bulk When Practical
Water conditioner, filter floss, and activated carbon are consumables you'll use indefinitely. Buying the largest container of Seachem Prime you can afford (the 2-liter bottle instead of the 250ml) drops the per-gallon cost significantly. The same applies to most liquid aquarium products.
Understanding Product Quality Online
One of the challenges with online shopping for aquarium equipment is that product photos and descriptions don't always match what arrives. A few ways to protect yourself:
Read Reviews Critically
Reviews are useful but require some skepticism. Look for reviews that mention specific tank sizes, fish types, or use cases similar to yours. A filter that works great in a 30-gallon tank may be inadequate for a 75-gallon. Ignore one-star reviews about shipping damage (that's not the product's fault) and one-star reviews with no detail.
Check Return Policies
Major retailers like Amazon and Chewy have generous return windows for most products. Before buying a more expensive piece of equipment, confirm the return policy. Some specialty electronics like UV sterilizers or dosing pumps have shorter return windows.
Verify Compatibility Before Buying
This matters most for replacement parts. Always confirm that a replacement impeller, O-ring, or spray bar is compatible with your specific filter model before ordering. Manufacturers update their models, and a part listed as compatible may not actually fit.
Saving Money on Aquarium Supplies Online
Use Cashback Portals
Rakuten and similar cashback portals give you 2 to 8 percent back on purchases at most major aquarium retailers. Stack this with a cashback credit card and you can save 4 to 12 percent on every order with no effort.
Join Retailer Email Lists
Marine Depot, BRS, and That Fish Place all run regular promotions. Joining their email lists means you'll know about sales before they expire. These aren't just 5-percent-off deals. BRS in particular runs sitewide 10 to 20 percent off sales a few times per year.
Consider Used Equipment for Large Items
For expensive equipment like protein skimmers, lighting systems, or large canister filters, the used market often offers 40 to 60 percent off. Check Facebook Marketplace and local aquarium club classifieds before buying new. A used Aqua Medic protein skimmer rated for 200 gallons can sell for $100 when new models cost $350.
For a curated selection of the best equipment options across categories, our roundup at Best Online Fish Supply Store compares the top retailers and products available right now.
What to Have on Hand Before You Need It
Running out of supplies when your fish are stressed is no fun. Keeping a small stockpile of critical items means you're never waiting on shipping when time matters.
Items worth keeping in stock: Seachem Prime (water conditioner), API Master Test Kit, filter floss or sponge media, an extra heater, and whatever medication you'd use for your fish type. For freshwater tanks, Seachem StressGuard and API Stress Coat are worth having around. For saltwater, a salinity refractometer and extra salt mix should always be on the shelf.
FAQ
Is buying aquarium supplies online cheaper than PetSmart or Petco?
Usually yes, often by 20 to 40 percent on equipment and dry goods. The exception is when a local store runs a genuine sale on a specific item. For ongoing purchases like food and filter media, online subscriptions through Chewy or Amazon Subscribe and Save almost always beat in-store prices.
Is it safe to buy fish online?
It depends on the seller and your experience level. Established online fish retailers like LiveAquaria and Dan's Fish have livestock guarantees and pack fish carefully. That said, fish can be stressed by shipping, which makes them more vulnerable to disease. Most experienced hobbyists recommend quarantining any fish you buy, whether local or shipped.
What's the best way to ship aquarium equipment to avoid damage?
You don't ship it, the seller does. What you can control is ordering from retailers with good packaging reputations. BRS and Marine Depot in particular are known for solid packaging. Avoid ordering large glass items (tanks, canister filter bodies) from unknown third-party sellers on Amazon.
Do online aquarium stores have return policies for livestock?
Most dedicated fish retailers offer a live arrival guarantee, typically 24 to 48 hours. If fish arrive dead or die within that window, you submit a photo and get store credit or a replacement. This doesn't cover fish that die after the guarantee period due to your water conditions, so have your tank properly cycled before ordering.
Key Takeaways
The best approach to buying fish aquarium supplies online is to use multiple retailers depending on what you're buying. Amazon wins on convenience and price for standard equipment. Chewy is best for food and consumables with auto-ship discounts. BRS and Marine Depot are the go-to for serious reef equipment. Always compare total prices including shipping before buying, use cashback portals, and stock critical supplies before you need them in an emergency.