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

I've never had luck with any fish I bought there. I bought three small baby goldfish from there and put them in a big tank. They were bad at first but the first batch died after three hours. Lucky, I was able to return them but it was kind of annoying. I kill fish but not that quickly. I did that two more times before the fish person at Walmart told me that the ammonia from the tank was probably what killed them. The next day, a tank that had twenty gold fish in it was down to two small ones, that died soon after. Since then, I've always noticed that the fish never look healthy and that they always seem over crowded for their tanks or empty.

If your fish died within three hours, it couldn't possibility be ammonia.  Ammonia builds up over time in the term of days.  No way it could kill fish that quickly.   Even if they were low quality weak fish.  

How big is a "A big tank"?   Please use gallon or liter when you refer to the size of a fish tank.    Otherwise you are not giving us any clue of its actual size.  

In order to find the cause of fish dying so quickly, we need more information.  
Did you use tap water?  What aquarium water conditioner did you use?  
Did you let their plastic bag sit in the fish tank water to allow the temperature be the same?  
Did you add the tank water to the plastic bag little by little to let the fish adapt to your water?  
Did you have a filter?  
Did you have an air pump?

Perhaps you need to read our article on Why did My Fish Die?


While Walmart indeed sells fairly weak fish in poor conditions, if they die within 3 hours it must be something you have done incorrectly.    Otherwise they would all just die in Walmart's tank within 3 hours, right?  

By the way, I do not quite get the part

Quote:The next day, a tank that had twenty gold fish in it was down to two small ones, that died soon after.

Were you referring to a fish tank at Walmart with 20 goldfish in it?

I have purchased Wal-Mart fish before, and also fish from another big box store, but I've never had to replace them quite that quickly. When you see a lot of fish in one aquarium your brain should go, "oh look, there's too many fish... they're stressed." If you still want some of those fish, look carefully at them for clues to their overall health. Clamped fins and tails means very stressed or sick or both. Drooping tail (unless the breed calls for it) also signifies a sick fish as most healthy fish hold their tails erect and spread out. White spots all over the fish is indicative of "Ich" and that fish should not be purchased. A bloated looking fish with pronounced scales is suffering from air bladder disease, and while it might not die, it will probably float upside-down as if it were dead. A fish with red spots on its gills is probably cursed with a condition that eventually will cause the poor thing's body to rot away while it's still alive. Watch out for ragged fins and tails, and weird "flashing" characterized by rubbing the body against objects or against the glass walls. Finally, if the fish you desire is difficult to catch... you've got a winner. Most sick fish will move sluggishly if they move at all when threatened. If the fish is too easy to catch, tell the store associate that you've changed your mind and pick out a different one.

I would not rule out ammonia that quickly. I have a 100 gallon tank and I keep *4* goldfish in it. Goldfish produce a lot of waste and if you are putting them straight in a new tank there is zero beneficial bacteria in there to process ammonia waste into harmless nitrates. If your tank is anything under 50 gallons, 20 goldfish could indeed poison themselves with their own waste in a few hours.

In any case, the problem is almost certainly in the water one way or another. Either ammonia or improperly prepared water in some way. Consider the possibilities: chlorine, stagnant, extreme temperature, contaminated (e.g. soap, insecticide), etc etc.

Start. Tanks. Slow. Test the water. Then either do a fish-less cycle or add one small fish that is hardy, like a guppy. And don't put 20 messy goldfish in anything smaller than a child's paddling pool. They produce a lot of waste.

Regardless of the reason that your fish actually ended up dying, I would strongly suggest that you buy your fish elsewhere in the future.  We have some chain as well as some independent pet stores in my area that are slightly more expensive when it comes to buying fish.  However, overall they take much better care of their fish and you're much more likely to get a fish that is healthier from the start.  I am fortunate because in our area we even have an entire store that is completely dedicated to the fish and pond aquarium enthusiast!  It is a really nice place to go for ideas, advice about fish, and to see all the cool and interesting types of fish you can get that you would never find at some place like Wal-Mart.

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.

(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.