What To Do When Your Fish Is Dying: Dealing With Dead Fish

It is so unfortunate to lose one of your much-loved fish. If you notice him dying the question is what to do when your fish is dying?

Can you save him?

Death can happen for a number of reasons. If you have spotted a distressed fish then you may be able to save him. In some cases, this may not be possible though.

In today’s post, I am going to show you what do do when your fish is passing away. I will show you the steps to save him if possible but also what you can do to protect the rest of the fish in your aquarium.

Why The Hell Are My Fish Dying All Of A Sudden?

When death happens in your aquarium it is so important that you work out what could be the possible cause. If it wasn’t a natural cause or old age then the other fish in the tank may be at risk.

The last thing you want is a mass exodus!

Taking the time to rule out the cause of death could be the savior of another fish in your aquarium.

Healthy Angelfish In Tank

Smaller fish tend not to live as long as the bigger varieties so if you got a few all at once then they may die around the same time.

This is the circle of life!

In some cases, death may occur due to other reasons. Here are my top three reasons for fish dying all of a sudden:

Ammonia Spike: An Aquariums Biggest Killer

This is the most common cause of fish death. Especially amongst new fish keepers. Even if you have been in the hobby for a while ammonia spikes can still occur.

What exactly causes ammonia to spike in the tank?

If this is a brand new tank then your ammonia can spike if you haven’t cycled your tank properly (click here to learn how). If you do not have enough good bacteria to deal with fish waste then the ammonia levels will rise. SeaChem Stability is perfect to help kickstart your good bacteria.

Death of another fish in the tank can also cause the ammonia to spike in your aquarium. When the fish dies it is going to release a large amount of ammonia. Deal with it quickly!

There are many different reasons why the levels could rise. Your job is to deal with it quickly:

Step One: Do a water test to confirm that an ammonia spike is occurring. You want to check the levels of ammonia, nitrites, and nitrates.

Step Two: If your instinct was correct and ammonia levels are raised then it is time to take drastic measures with a large water change of at least 50%. This could kill some fish but if you don’t the ammonia will kill more.

Step Three: Treat your water with a dechlorinator. SeaChem Stability and add an ammonia reducer. I would highly recommend SeaChem Prime this will detoxify the ammonia and nitrites and nitrates.

Step Four: After you have treated the water it is time to monitor the situation. Check the water again within one hour. If no change you should add some more SeaChem Prime. If you notice an improvement check the next day.

After 24 hours, if you still see no improvement another big water change is the best way forward. Again Treat the water after the water change.

Overcrowding Your Aquarium & Poor Water Quality

Again this is more common among new fish keepers. I get it you are very enthusiastic and want more and more beautiful fish to look at.

When you add more fish you are adding another source of ammonia!

Adding too many fish or adding new fish in large quantities will knock off your water parameters.

Poor water quality can cause death in an aquarium.

Do you have more than 1inch of fish per gallon of water in your tank? If so your tank is definitely overcrowded. It is time to get rid of some fish before death occurs.

If death is already occurring no good fish keeper will take your fish, you may have to lose them to deal with your problem.

Takeaway: Do not crowd your tank! This is a sad reason for fish death!

Oxygen Deprivation Is More Common Than You Think

Fish need oxygen like any living animal. In most cases, oxygen will be in abundance but for people that are new to the hobby, they might not know how to oxygenate their tank.

If you notice fish dancing on the surface of the tank this is not a cute little welcome dance. This is your fish trying to get more oxygen into their little bodies.

Oxygenating your tank isn’t as hard as you may think.

Fish Bowls Cause Low Oxygen

Fish bowls are the number one cause of oxygen deprivation. There is not enough surface area for oxygen to pass into the water.

Yes, some oxygen will get in but it is often not enough.

If you notice a gasping fish then you should add an air stone this will agitate the surface but also pump air into the tank. Just keep the flow low. If you notice it is battering the fish about simply turn the flow down.

A Fish Killing Badass Disease: Most Common Is White Spot (Ich)

Ich sometimes is known as White Spot and is the worst and most common fish disease. What exactly is Ich and how do we get rid of it from our tank.

Whitespot is a protozoan fish parasite. Its scientific name is Ichthyophthirius multifilis and in the US this is frequently abbreviated to its other common name of Ich.” – Practical Fish Keeping

Like some human parasites, Ich is found in all fish. In normal circumstances, this will not cause any harm to your fish. However, when the fish are stressed or their immune system is compromised ich could manifest and become lethal.

It is common during the winter months for Ich to wreak havoc on your tank. The sudden drop in temperature can play games with the stability of your tank. Instability with the water parameters can cause Ich to develop into the badass fish-killing disease.

The parasites themselves aren’t visible to the human eye but cysts that house these parasites are normally visible. These look like speckles of sugar on the body, fins, and gills of your fish.

These could even develop in the eye of your fish.

You may also notice that your fish is very lethargic, less active or gasping for breath (pay attention to the gills). If one fish has it then you should assume all it’s tank mates do. Ich is very contagious.

It is best to move fish to a quarantine/hospital tank while you treat. Some medications can stain parts of the aquarium. SeaChem’s Paragaurd is the most widely available and the most effective. Always follow the directions on the bottle for dosing and how to use.

As well as medicating fish you should turn the temperature of the water to around 82 degrees Fahrenheit. This should be enough to kill off the parasite. If you are not using your main tank you should still turn the temperature up to kill any parasites before the fish return.

Treatment should last about 7 days in the hospital tank. Daily water changes will be a must in both tanks.

CPR Failed: What Should I Do With The Fish Corpse

Sometimes even when you do all the right stuff you may lose a fish or two. Especially if they are already in the process of dying. It leads us to the unfortunate task of dealing with a fish corpse.

The first thing you should do is remove from your tank. The dead fish is going to release a huge amount of ammonia and if not dealt with correctly more fish could die.

You should also note that if left in the tank it will rot quicker and other tank mates may nibble. If this fish suffered a disease your healthy fish may contract the disease.

Once the fish is removed you have a few options but you will have to check with the authorities to make sure it is allowed. First, put your little friend in a ziplock bag or a little matchstick box. It’s a bit nicer than just disposing of the fish.

Burial seems like the nicest option but you still have a few problems. The smell is quite pungent and could attract outdoor critters. Make sure you dig a deep enough hole. You could place a rock over the top and this would be like a memorial.

This isn’t always practical if you have a lot of fish.

Burning/cremating would be the next option but you will need to check with authorities to make sure you are permitted to start a fire.

Your last option would be to put the matchstick or ziplock bag in an outdoor bin that is emptied frequently. This would probably be my go-to option.

Dealing with a dead fish is never nice but you need to remove the body. A decomposing fish is not a pleasant smell. In hot temperatures, the body will rot much quicker.

Protect Your Aquarium & Save The Rest Of Your Fish

Now that your poor little guy has been removed you have to protect the rest of your fish. If you were able to work out what the cause of death was then you can treat the rest of the tank.

If your fish suffered a contagious disease it is best to put all your other fish into quarantine. This means you can medicate them against the disease. Even if there are no visible signs they might still be carrying the fish-killing infection.

The reason I suggest a hospital tank or quarantine tank is because some fish medications will stain parts of the aquarium. Plus you want to remove the carbon from the filter.

With the other fish in quarantine, you can cleanse the main tank by turning the temperature up to around 84 degrees Fahrenheit. This is high enough to kill most bacteria but you will need to be careful as it might kill your good bacteria.

After 48 hours and a water change add some SeaChem Stability to kickstart the good bacteria. You will also want to turn the temperature back down to the normal range.

Add some SeaChem Prime too. This will just reduce the toxicity of ammonia, nitrites, and nitrates. There is a chance your dead little friend could have released a lot of ammonia.

Before you add the quarantined fish back you should test the water to ensure that the ammonia and nitrites and nitrates are not raised. Once sure you can add the fish back to your main aquarium.

Summary: What To Do When Your Fish Is Dying?

Following these tips will help revive your ecosystem after the death of one of your fish. Unfortunately, you may lose more than one fish at this time. This could be due to an ammonia spike or the disease could be lingering in your aquarium.

Try and work out what the cause of death was so you can treat the other fish accordingly. Just because they aren’t showing any signs or symptoms doesn’t mean that they aren’t affected.

You want to do a big water change around 40-50% and continuously test your water. If you notice an ammonia spike then take action quickly. Ammonia is a fish killer and you don’t want your fish to be gasping for their life.

Unfortunately there really isn’t a nice way to dispose of the dead fish but try and treat it with a little respect.

So there you have it you now know what to do when your fish is dying. Do you have any experience or tips to deal with the death of a fish?

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