My new fish died quickly after purchase. What are common reasons?

Related Answers from Veterinarians

• Answered By Lauren Kennedy, DVM

  Veterinarian

  There can be many reasons your fish passed away. Most pet stores will replace your fish for no charge if it dies within a certain amount of time. I would also recommend bringing in a sample of the water your fish was in so they can check the pH of the water and make sure it is appropriate for the type of fish you purchased.

  

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• Answered By Angel Alvarado, LVT

  Licensed Veterinary Technician

  Published on June 30th, 2018

  I'm sorry for the loss of your fish. If the tank was a "new" tank, it likely was not sufficiently cycled. The fish may have died after being exposed to high levels of ammonia or nitrites.
  A fish tank should be cycled for 4-6 weeks before fish are added. This allows time for beneficial bacteria to populate the filter and substrate. These bacteria are responsible for breaking down wastes (fish waste, decaying plants, uneaten food) to prevent a buildup of ammonia, nitrites and nitrates.
  A tank can be cycled with fish, however this requires close monitoring of water chemistry and frequent partial water changes to stabilize chemistry and maintain water quality. Cycling with fish increases the risk of fish loss.

  

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• Answered By Angel Alvarado, LVT

  Licensed Veterinary Technician

  Published on August 5th, 2018

  Anytime there is an unexpected loss of fish, water chemistry should be checked. Use a home test kit ( https://www.petco.com/shop/en/petcostore/product/api-freshwater-master-test-kit# ) or submit a water sample for testing. Most pet stores will do this for free or for a small fee. Confirm an absence ( 0 ppm ) of ammonia and nitrites with a nitrate level of 20 ppm. pH can range between 6.5 and 8, water temp should be 65 F to 75 F.
  If chemistry and water quality are within normal parameters, then illness or aggression would be other reasons for the loss. It is always recommended to quarantine fish in a separate tank for 2-4 weeks prior to adding them to the main tank. During this time, they can be treating for infection or parasites. I am sorry for the loss of your fish.

  

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• Answered By Angel Alvarado, LVT

  Licensed Veterinary Technician

  Published on June 14th, 2018

  It is no trouble at all. It is why we are here!
  The first thing to check would be water chemistry. This can be done using a home test kit or by submitting a water sample for testing. Most pet stores will do this for free or for a small fee. Aim for 0 ppm ammonia and nitrites with a nitrate level of 20 ppm or less. Perform a partial water change, no more than 30% total volume, daily to stabilize or improve water chemistry. Use only aged or conditioned water that is temperature matched to prevent stress or shock. The species of fish you have do best in the mid to high 70s F up to about 82 F.
  If you have a newly set up tank, it may not have cycled properly or adequately. This would have led to toxic levels of ammonia which likely killed your fish. A tank needs to run, without fish ideally, for 4-6 weeks to establish a Nitrogen Cycle. This time period allows beneficial populations of bacteria to colonize the substrate and filter media. These bacteria are responsible for breaking down ammonia and nitrites into nitrates which can dissipate naturally, be used by live plants or be filtered out.
  A tank can be cycled with fish, however, close monitoring of chemistry and frequent water changes are required to minimize the risk of fish loss.

  

  1Pet Parents found this answer helpful