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What To Do When a Fish Dies In Your Tank?

The question sounds like the answer should be obvious however it might not always be obvious. When a fish dies in your tank you really should consider the sound advice below.

My Fish Died What Do I Do?

When a fish dies in your tank you need to get the fish out of your aquarium ASAP.

However, before we go in depth on what you should do when your fish dies let’s back it up a bit and look at how we identify when a fish has actually died or possibly gone missing.

How to Identify When a Fish Has Died or Gone Missing

Before you can say your fish has died you must first identify that a fish as indeed passed away. Sometimes a fish just vanishes. If you cannot find a fish just by looking in the tank then you must start searching for it. You do not want it to rot in the water getting the other inhabitants sick and possibly dying as well. Here are some tips on where to find the missing fish.

  • Check the floor around the tank because if there are openings as some fish like to jump and might accidentally jump out of the water. Other fish might get chased and end up flying out of the tank by accident.
  • Check the filter intake and turn the filter off checking in the filter as well.
  • Check in caves, crevices and around plants in the tank.
  • If the fish does not turn up looking in these locations then chances are the fish was eaten. In this case there really isn’t anything else to do other than maybe considering who the culprit it is and deciding if other fish are safe or in danger.
  • If you do find the fish is it really dead? Some fish like to wedge themselves in tight locations as it makes them feel safe.

Once a Dead Fish is Found – Remove the Dead Fish

When something dies in the tank it is always a good idea to try to determine how the fish might have died.

  • Was it bullied to death?
    • If it looks like the fish was bullied and picked at until it died then you will probably want to find out what fish was responsible and punish it accordingly. Just kidding. You do want to figure out though if other fish are in danger or determine if you were feeding the fish enough food and or the correct type of food.
  • Did the fish get sick – catch a disease?
    • If the fish died from a disease it would be wise to identify what the problem might have been and treat the tank and remaining fish if necessary or keep a very close eye on the tank afterwards to see if any disease pops up in the fish.
  • Does it look like old age?
    • Sometimes it’s just a matter of old age and it was time for the fish to pass on. Nothing really to be concerned with if you feel this is the case.

dead clownfish

How Do the Rest of the Aquariums Inhabitants Look?

  • Of course if there is disease in the tank you want to deal with it ASAP. Check to see if the rest of the fish look healthy or are also showing signs of sickness.
  • Be wary if more fish start to die. Maybe the fish will look fine yet another one dies a couple days later. If so then you most likely have a problem with the water parameters.
  • Put remaining fish in a quarantine tank if you find out you need to treat the fish and or tank. If you don’t have a quarantine tank then you better get one set up just in case an emergency like this pops up again in the future. Want to know how to set up a quarantine tank?
  • Test the aquarium water. Test the tank water for Nitrite, Nitrate, Ammonia and even PH. Check the temperature as well as sometimes aquarium heaters are faulty and heat up or cool down when they are not supposed too.


What To Do With My Dead Fish Now?

So you have your dead fish and now it is time to dispose of the body so what to do?

  • I am sure there have been millions of fish that have been flushed down toilets over the years. You could do that or you could consider that if you do flush the fish down the toilet that it might end up getting stuck somewhere along the sewer because of the hard body of the fish. Plus you loved that fish and enjoyed so many hours watching it and it was part of the family. I vote you dispose of the fish some other way.
  • We bury our pet dogs and cats and whatever other types of animals we own so I vote to bury the fish in mother earth. If you have a backyard then it is easy to dedicate an area to burying your pets. Having a simple ceremony celebrating the life and fun you had enjoying the pet should be recognized.
  • If you don’t have a yard how about going out to the forest or field somewhere that you know will not get disturbed and burying the fish in that area?
  • In some cultures humans burn the dead in a ceremony on top of fire. You could set up a fire in the backyard or a location safe for fires and have your own burning ceremony.

When is it Safe To Restock the Tank?

So now over a bit of time you are thinking you might want to restock the tank. I would recommend you take a couple of weeks before doing so to ensure there was no sickness in the tank. I know you might have your eye on a cool looking fish that would look great in your tank but do yourself a favor and save your money and heartache. Wait a while until you are certain it is safe to add more fish to the aquarium.

When I decided I needed to write this article I thought I would check online to see if there were other questions fish owners might be asking related to the topic of what to do when your fish dies and found a few I thought would be helpful to answer.

Do Fish Float or Sink When They Die?      floating dead fish

Initially they might float considering they probably have oxygen in their bodies and if the current is strong enough to get them to start rising to the top and able to keep the fish at that height in the tank.

My experience though is that eventually they all end up either on the bottom somewhere or the filter intake sucks them up to the tube if the fish is small enough.

Here’s How to Clean a Tank When a Fish Dies

Now this question definitely deserves its own article however just at a high level I can tell you now that you should go through your tank giving a thorough cleaning depending on how your fish ended up dead. So your fish died what do you do as far as cleaning the tank goes?

  • If the fish died from what looks like old age then a filter cleaning is probably sufficient. I would use water from your quarantine tank to clean the filter and not water from the tank the fish died in.
  • The fish had an obvious disease then you might quarantine the other fish and go through cleaning the substrate, filtration, plants and whatever else you have in the aquarium.
  • If your fish was bullied to death then cleaning the filter and vacuuming the substrate is most likely all you need to do.
  • If the tank was almost due for a water change then do that as well regardless of how the fish died.
  • Clean the tank like you would any other time.

If a Fish Dies Should You Change the Water?

Unless you just changed the water within 24 hours I would say go ahead and change the water. Do a 25% water change.

Why Do Fish Die After Cleaning Tank?

This is a great question and unfortunately this happens all too often with newbies to the aquarium hobby.

When cleaning the tank if you are using any type of product that is harmful to fish it will most likely kill the fish. Depending on the hardiness of your tanks inhabitants they can only withstand so much chemical or other ingredients dangerous to them before they succumb.

Always use products that are aquarium safe to clean a tank and when cleaning the filter use water from the aquarium your fish are in or if you are smart and have a sick tank running all the time you can use that water as well.

Why are My Fish Dying in My New Aquarium?

Just like the previous answer this happens all too often with newbies to this hobby.

Of course without actually investigating each individual aquarium that this happens to it would be quite difficult and impossible to say with 100% certainty why however if it is a new aquarium my first thought is that the tank was not run longer enough to go through the Nitrogen cycle before the owner bought new fish for the tank. If you are new to the hobby and are not familiar with the Nitrogen cycle I recommend you go read my article on the topic. Why you need to understand the Nitrogen Cycle.

Once you understand this process and how it affects the health of your tank you will have great success in this hobby. There are ways to speed up the process if you need to do that.

Conclusion on What To Do When a Fish Dies in Your Tank

I hope I was able to help you figure out what you needed to do if your fish dies and maybe you learned a few other things as well. Just remember that fish are living creatures and deserve the best care possible whether they are still alive or have just passed on.

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