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FISH / new pets

A Set-up Guide for Your New Catfish

Tips for home and health


Four things to know about your catfish

  • Catfish can live from seven to 15 years
  • They can grow up to 1 foot long
  • Many catfish prefer living in groups of three or more
  • Big catfish need to live with similar-sized tank-mates; they may eat smaller ones

Your catfish’s new home

Aquarium & stand

  • Cory catfish, which grow to be about 4 inches long, can live in 5 to 10-gallon tanks. Larger catfish require at least a 30-gallon tank.
  • Keep the aquarium near a power source in a low-traffic area, away from direct sunlight and drafts.
  • Water weighs about 10 pounds per gallon. Pick a sturdy, stable base for your aquarium, and then fill the tank with water.
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What to put in a catfish’s tank

  • If you will be using an under-gravel filter, add that first.
  • Layer about 3 inches of gravel on the bottom of the tank. (That works out to 1½ pounds of gravel per gallon of water.) Rinse the gravel before putting it in the aquarium.
  • Fill the tank about halfway up with dechlorinated water.
  • Add thermometers and other necessary equipment.
  • Time to decorate! Add plants, rocks and fish furniture.
  • Finish by filling the tank the rest of the way with water.
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  • An aquarium filter should be able to process all of the water in the tank three to five times an hour. For example, the filter in a 20-gallon tank would need to push through at least 60 gallons of water each hour. Follow the manufacturer’s instructions for choosing and setting up the filter.
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Heat & lights

  • Check the temperature your fish will need before you bring them home. Catfish require warm water that’s between 74 and 78 degrees Fahrenheit.
  • Choose an aquarium heater with 5 watts of power for each gallon of water in the aquarium. A large aquarium may need a heater at either end.
  • Wait 15 minutes after filling the tank before turning on the heater.
  • Place the heater close enough to the filter to distribute the warmed water.
  • Run the tank’s filter and the tank’s hood light for 24 hours, then check the water temperature and adjust the heater if necessary.
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Adding catfish to your aquarium

  • Bring your catfish home right away after you buy them.
  • Place them in your aquarium — inside their bag — for 15 minutes so they can get used to the new water temperature.
  • Next, use a net to transfer the catfish into your aquarium. Try not to bring too much of their old water with them.
  • Add only three catfish at a time to make sure the filter can handle all the new action in the neighborhood.
  • The chemical balance in your aquarium will change with every new fish you introduce, so check the tank’s pH, ammonia, nitrite and nitrate levels regularly.
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Keeping catfish healthy

If your catfish display any of these symptoms of illness or distress, talk to a PetSmart store associate or a veterinarian familiar with fish health:

  • Decreased appetite
  • Fins clamped to the sides
  • Scraping body on rocks
  • Abdominal swelling
  • Inflamed or discolored skin or fins
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FREE water quality testing

PetSmart offers free aquarium water testing. Bring in a sample and we can test its quality within minutes.

General aquarium health and environmental guidelines

  • Fish and aquatic animals can transmit zoonotic disease to humans. Wash your hands with soap and water before and after interacting with your aquarium. Children, pregnant women, elderly people and those with immune-system problems should take extra care.
  • Keep fish away from food and areas where food is prepared.
  • Never release fish into the wild.

PETSMART CARES Pets purchased at PetSmart are part of our exclusive Vet Assured™ program, designed by PetSmart veterinarians to help improve the health and well-being of our pets. Our vendors meet a high standard in caring for pets and screening them for common illnesses. This program also includes specific standards for in-store pet care.

The PetSmart Promise: If your pet becomes ill during the initial 14-day period, or if you’re not satisfied for any reason, PetSmart will gladly replace the pet or refund the purchase price.