How to Buy Pet Fish in the United States | PetzLover

Which pet fish suits your home?

Start with the setup you can maintain, not the fish you saw first.

Freshwater is the usual start. Saltwater tanks hold fewer fish for their size and suit people who have already kept a freshwater tank. Water weighs about 8.3 pounds per gallon, so a large tank needs a sturdy stand and floor.

Why must the tank be ready before you buy fish?

Fish waste produces ammonia, which is highly toxic. In a cycled tank, filter bacteria turn ammonia into nitrite and then into much less toxic nitrate. A new tank has none of these bacteria yet.

1. Place the tank away from direct sun and air vents, and fill it with tap water treated with a conditioner that removes chlorine and chloramine.
2. Run the filter, and the heater for tropical fish, for about 4 to 6 weeks.
3. Test the water: ammonia and nitrite should read zero before fish go in.
4. Add one or two fish at a time so the bacteria can keep up.
5. Float the closed bag for about 20 to 30 minutes so temperatures match, then net the fish in. Never pour the bag water into your tank.

After that, VCA suggests partial water changes every 2 to 4 weeks.

Where can you find pet fish for sale in the US?

• Local fish stores: you can see the tanks and buy equipment at the same time.
• Home breeders and hobbyists: often sell livebearers, bettas, cichlids and plants. Many local aquarium societies, often members of the Federation of American Aquarium Societies, hold swaps and auctions.
• Koi dealers and koi clubs: clubs affiliated with the Associated Koi Clubs of America connect pond keepers and sellers.
• Owners selling a whole tank: people moving often sell fish with the equipment.

You can browse pet fish for sale, filter by location and save the search to get an alert when a matching listing appears. Message the seller through PetzLover and prefer sellers you can visit, so the fish avoid a long journey.

What should you ask a fish seller before you buy?

• How long have you had these fish, and did you breed them?
• What temperature and pH do you keep them at?
• Any deaths, white spots or treatments in this tank in the last month?
• What do they eat, and how often?
• How big will this species grow, and what can live with it?
• For saltwater fish: was it captive-bred or wild-caught?
• For koi: how long were they quarantined?

Ask about adult size especially: goldfish and koi are often sold small and outgrow their first tank.

A University of Sydney study of US online sellers found that almost 90 percent of marine aquarium fish were taken from the wild, many from Pacific and Indian Ocean reefs. Captive-bred fish such as clownfish are a better choice where available.

How do you check that pet fish are healthy?

CDC advice is simple: pick fish that are active and swim normally, with smooth, shiny scales that are not discolored, no bumps and intact fins. Look at the whole tank, because disease spreads through shared water.

• White, salt-like spots on the body or fins can be ich, a contagious parasite.
• Clamped fins, gasping at the surface or rubbing against objects.
• Dead or sick fish in the same tank.
• Ulcers, cloudy eyes or a swollen belly.

Quarantine new fish in a separate tank before they join your others. Hobbyists commonly quarantine for 3 to 4 weeks, and the Merck Veterinary Manual suggests at least 30 days at about 75°F for new koi because of koi herpesvirus.

How much do pet fish really cost?

The fish are usually the cheapest part. Equipment and upkeep cost more.

The betta, setup and upkeep figures come from a 2026 US cost guide by The Vet Desk and the koi range from PetMD; prices vary by region. Budget also for a quarantine tank and, for ponds, a pump, liner and aeration.

Which fish are illegal to buy or keep in the US?

The U.S. Fish and Wildlife Service lists some fish as injurious wildlife under the Lacey Act, including the whole snakehead family, walking catfish, bighead, silver and black carp, and since 2016 species such as the zander and wels catfish. Without a federal permit they cannot be imported or shipped between the continental US and places such as Hawaii and Puerto Rico. Since a 2017 federal appeals court ruling, the listing does not bar moving them between continental states, but many states ban them outright.

California, for example, restricts piranhas, snakeheads, gars, freshwater stingrays and several tilapia, which cannot be imported, transported or possessed without a permit, and Texas prohibits possessing or selling live piranhas. The Lacey Act also makes trading fish in violation of state law a federal offense, so check with your state fish and wildlife agency before buying an unusual species.

Selling your own fish later? See how to sell pet fish. If someone is giving fish away, read how to get free pet fish safely, and if you are taking over an established tank, how to take in rehomed pet fish covers the move.