Why did my fish die in 3 hours? (Fish bought from walmart)

(07-08-2016, 05:00 AM)joshposh Wrote: There are a lot of factors that go into why fish die so quick in a new tank with water.  It is never a simple answer and it surely isn't as simple as placing fish in water.  There are water chemistry, and aeration that goes along with it.  

You need to check the PH levels of the water, as well as temperature and proper aeration.  Buy a testing kit and check to see what is the optimum levels for gold fish to thrive.  

Also you need to acclimate the fish to the new water temperature by floating them in the bag and leave them in the tank water until the temperature of the bag and tank are the same.  The fish will go in shock if you just dump them in the water and die soon after.  HINT HINT.

Finally, you need to make sure that there is more then enough aeration in the tank.  Let the filter and the air pump (if that is your current set up) run for a few hours or even days before the fish arrive.  let the water cycle through the new mechanism and you can work out the bugs if they present themselves.

Water temperature and PH are not much of a concern for fish as long as the reading is not too extreme.   It is what the acclimating for.   Letting the fish bag float in the water is not just to get the same water temperature.  You also need to add the water from the tank into the bag little by little to let the fish get used to other aspect of the water too before you release them into the tank.  PH, hardness, etc. are parts of it.  

The acclimating process could take hours.  The longer the better.    

A lot of people skipped the acclimating part when they brought fish home.   Then they asked why the fish died within hours.   Nothing can kill fish faster than get them into shock due to lack of acclimating during the first time introduction to a new tank, as well as during transferring to different fish tanks or during the water change.   


Letting the aquarium run for a few hours or days is not enough.    It will in fact do nothing.   

What you need is to do a fishless cycling before introducing the fish.    To do a fishless cycling, you need a source of ammonia.  It can take over a month to finish it without heaving seeding.   With heavy seeding, it can be as short as a week or even a few days.   The key is to get enough good bacteria colonize the filter media, so they will feed on the ammonia produced by the fish later on.   Ammonia will kill the fish, but not as quickly as the shocking effects unless it is in extremely high concentration.