Freshwater aquarium gear for goldfish, bettas and tropical fish
Test kits, a sponge filter, a starter tank and fish food, picked from published ratings and expert guidance. Start with cycling the tank and treating tap water, then choose gear to fit your fish.
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Pets this page covers
Fish and aquariums
Cycle the tank before stocking and add fish gradually. Test the water and change it on a schedule, and quarantine new fish in a separate tank.
Goldfish
Goldfish and other cold-water species can do well at room temperature, so they do not need a heater. We found sinking pellets that suit them, and Merck advises a lower stocking level for goldfish.
Betta fish
Small tanks such as betta tanks may need water changes up to 50% weekly. A gentle air-driven sponge filter suits bettas, and some reviewers feed them the Fluval pellets listed below.
Freshwater tropical fish
Tropical fish need a heater and a separate thermometer. We have not verified a heater pick yet, so none is listed.
What to look for
- Cycle the tank before stocking. Beneficial bacteria turn ammonia into nitrite and then nitrate. Natural cycling takes about 4 to 6 weeks, and fish should be added gradually, one or two at a time. Source: Merck Veterinary Manual
- Treat tap water. City water often contains chlorine or chloramine, which is toxic to fish and to beneficial bacteria, so dechlorinate new water. Source: Merck Veterinary Manual
- Do not overstock. A common freshwater guideline is 1 inch of fish per 12 square inches of surface area, reduced for goldfish and cold-water setups. Source: Merck Veterinary Manual
- Heat tropicals, not goldfish. Tropical fish need a heater and a separate thermometer, while goldfish and other cold-water species can do well at room temperature. Source: Merck Veterinary Manual
- Small tanks such as betta tanks may need water changes up to 50% weekly. Source: Merck Veterinary Manual
- Test and maintain on a schedule. Test pH, alkalinity, ammonia, nitrite and nitrate about every 2 weeks, change water about every 2 weeks, and replace filter cartridges about monthly or when clogged. Source: Merck Veterinary Manual
- Quarantine new fish for 30 to 60 days in a separate tank. Source: Merck Veterinary Manual
- Wash hands before and after tank care and wear gloves if you have cuts. Dump tank water in a tub or laundry sink, not the kitchen sink, and keep children under 5 and immunocompromised people away from tank chores. Source: CDC
Research picks
These are research picks drawn from published ratings and expert sources, not our own lab tests. Prices and ratings were seen on 2026-10-23 and can change.
Test kit Freshwater fish Research pick
API Freshwater Master Test Kit (800 tests)
Anyone cycling a new tank or doing routine water checks.
Liquid drop kit with over 800 tests, 4 tubes and a rack. Chewy lists pH, high-range pH, ammonia, nitrate and hardness, and results are read by matching color cards. Check the box for the full parameter list before you buy.
Skip it if: You want fast digital readouts, or you have a saltwater tank.
Price seen: $35.59 on Chewy (list $50.48) | 4.7 of 5, 323 ratings / 186 written reviews, Chewy
See it at Chewy Affiliate link
Air-driven sponge filter Betta, shrimp, fry, quarantine Research pick
Aquarium Co-Op Green Easy Flow Sponge Filter
Bettas, shrimp tanks, fry, quarantine tanks, and any tank where gentle flow and a safe intake matter.
Foam sponge with an air collar, a curved uplift tube and a weighted base, designed to be reusable and clog-resistant. Sold in nano to large sizes. The brand is itself a hobby retailer, so an independent expert source is not verified.
Skip it if: You want strong flow or a hidden-in-the-back look, or you do not want to run an air pump (pump and tubing are sold separately).
Price seen: $9.99 (nano), $11.99 (small), $12.99 (medium), $14.99 (large), brand site | No average shown. 3,453 reviews, 92% five-star (reviews may include grouped related products), aquariumcoop.com
See it at Aquarium Co-Op Not an affiliate link
Tank kit Freshwater fish Research pick
Aqueon Smart Clean Filtration LED Starter Kit, 20 gal
First-time owners who want a one-box setup.
Glass tank, LED hood, internal SmartClean filter with cartridge, preset heater, thermometer, net, and food and conditioner samples.
Skip it if: You want a long-term setup (the internal filter is basic) or a planted tank.
Price seen: $144.39 on Chewy (list $189.99) | 4.4 of 5, 39 ratings / 28 reviews, Chewy. Chewy notes many reviews are for the 10 gallon version.
See it at Chewy Affiliate link
Goldfish food Goldfish Research pick
Omega One Medium Sinking Goldfish Pellets (8 oz)
Goldfish. Sinking pellets reduce gulped air.
A 4 mm sinking pellet with fresh fats, omega-3 and omega-6, and salmon-skin pigment. The full ingredient list was not shown on the page.
Skip it if: You keep surface feeders or fry (this is a 4 mm medium pellet).
Price seen: $9.99 on Chewy | 4.4 of 5, 149 ratings / 71 reviews, Chewy
See it at Chewy Affiliate link
Tropical fish pellets Community tropicals, bettas Research pick Limited reviews
Fluval Bug Bites Color Enhancer (4.4 oz)
Community tropical fish and bettas. Reviewers mention bettas, angelfish and gouramis.
Black soldier fly larvae is the first ingredient, with shrimp (astaxanthin) and salmon. Vitamin-fortified.
Skip it if: You need a fully herbivore diet.
Price seen: $10.96 on Chewy (list $22.99) | 4.6 of 5, 43 ratings / 12 reviews, Chewy (low volume)
See it at Chewy Affiliate link
Water-change tool Tall tanks Research pick Limited reviews
Python No Spill Clean and Fill, 30 in gravel tube add-on
Tall tanks that need extra reach.
A longer gravel tube for an existing Python water-change system.
Skip it if: You do not already own the Python system, since this is an add-on tube and the main system is sold separately.
Price seen: $32.99 on Chewy | 4.4 of 5, 5 ratings / 3 reviews, Chewy (very thin)
See it at Chewy Affiliate link
Check the current price and availability before you buy. Links go to retailers and brands, and none are affiliate links yet. We have not checked recall databases for every item, so look up recalls before you buy.
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