Skip to Content

15 Reasons Your Angelfish Is Dying!

Angelfish are constantly going from strength to strength within the fish keeping community in terms of their popularity but with so many people who are new to fish keeping having angelfish in their tank, we commonly see people having a wide range of problems.

One of the more common problems that we have seen people having recently is with their angelfish dying and unfortunately, in many of these cases, the death of their angelfish was totally avoidable!

This is why we have decided to publish this article going over the more common causes of angelfish dying in the hope that we are able to help as many of our readers as possible.

Some of the issues that we will be covering below are surprisingly easy to detect and fix in your tanks making the problem a quick and easy fix. On the flipside of that though, there are some serious issues that can be more challenging to fix too.

Genetic Issues In The Fish!

Due to some of the more expensive and popular angelfish having a very specific color or pattern, breeders have been encourages to inbreed their angelfish stock to meet demand and maximise profit.

Unfortinatley, this has resulted in a number of genetic issues in many types of angelfish.

Some of these issues can be managed with proper diet and a nice large tank but others can prove fatal within years or even months without you even being able to treat the issue.

Low Quality Water!

One of the biggest problems that angelfish keepers run into is having low quality water in their tanks.

Angelfish are very sensitive to water conditions and even a small change in your tanks water parameters can cause big problems for your angelfish, especially if the angelfish is young or old due to the additional sensitivity that age bracket has.

Thankfully, issues with water quality are very easy to fix in most cases and more often than not, a partial water change should be able to correct the issue and your angelfish will be back to full health within a week.

An Unsuitable Diet!

While angelfish are not as fussy as some other fish when it comes to their diet, they still have very specific nutritional needs that need to be met in order for them to stay healthy and thrive in your tank.

A lot of angelfish keepers make the mistake of feeding their angelfish the same food that they feed their other fish which can often be unsuitable for angelfish and cause health problems down the line.

To avoid this, we recommend getting a high quality angelfish food that is designed to meet the specific needs of angelfish. This will ensure that your angelfish are getting all of the nutrients that they need to stay healthy and happy.

You also have to realise that different types of angelfish can have a very different diet to each other. As we covered in our Coral Beauty Vs Flame Angel comparison article, both species are angelfish and both are omnivores but one prefers plant-based food where as the other prefers meat based food.

This is very common with angelfish so always research the preferred food of your specific angelfish if you do think that it may be having problems with eating and taking nutrients on board.


Disease is one of the more common angelfish problems but it can also be one of the hardest to diagnose and treat.

The first thing that you need to do if you think that your angelfish may be sick is to quaranteen the fish in a separate tank. This will stop the disease from spreading to your other fish and will also make it a lot easier to treat the angelfish.

Once your angelfish is in quarantine, you need to take a close look at it and see if you can identify any of the more common signs and symptoms of disease.

Some of the more common signs to look out for include:

  • Clamped fins.
  • White spots on the body or fins.
  • Bulging eyes.
  • Loss of appetite.
  • Erratic swimming.

If you can identify any of these signs, we recommend taking a water sample from your tank to your local fish store or vet for testing. This will help you to identify what disease your angelfish has and how best to treat it.

One of the most common diseases that angelfish suffer from is ich (ichthyophthirius multifilis). This is a parasitic disease that can cause your angelfish a lot of distress and if left untreated, can be fatal.

The good news is that ich is very easy to treat and as long as you catch it early, your angelfish should make a full recovery.

Another common disease that angelfish suffer from is velvet (dactylogyrus vastator). This is another parasitic disease that is very similar to ich in the sense that it can cause your angelfish a lot of distress and can be fatal if left untreated.

Velvet is also very easy to treat but as with ich, the sooner you catch it, the better.

Stress And Anxiety!

Angelfish are very sensitive creatures and even something as small as a change in their tank mates or the addition of a new piece of décor to their tank can cause them a lot of stress.

This is why it is always important to take things slow when making changes to your angelfish tank and to make sure that your angelfish have had a chance to adjust to the new changes before making any more.

If you do notice that your angelfish are looking a bit stressed or anxious, we recommend adding some floating plants to their tank. These will help to create some hiding places for your angelfish and will also help to reduce the amount of stress that they are feeling.

You should also make sure that you are not overfeeding your angelfish as this can cause them a lot of stress. Overfeeding can also lead to health problems such as obesity and swim bladder disease so it is always best to stick to the recommended feeding amounts.

Issues With O2 And CO2!

One of the more common problems that angelfish keepers face is a lack of oxygen in their tanks. This can often be caused by overstocking your tank or not having enough aeration in your tank.

Either way, a lack of oxygen in your tank can cause serious health problems for your angelfish so it is always important to make sure that your tank is properly aerated.

Having too much CO2 in your tank can also cause problems with your angelfish. This is because CO2 is heavier than oxygen and so it will sink to the bottom of your tank where your angelfish spend most of their time.

This can cause your angelfish to become suffocated and can even lead to death so it is always important to make sure that you have the correct levels of CO2 in your tank.

Problems With Parasites!

As we mentioned earlier, angelfish are very susceptible to parasites and so it is always important to keep an eye out for any signs of parasites in your tank.

Both internal and external parasites can cause issues with your angelfish and in most cases, they are easy to spot.

External parasites are easier to see as you will often see them on the skin of your angelfish with the texture and/or color of the skin changing due to the parasitic infection.

Internal parasites can be less common to confirm but your angelfish will usually look fatter than usual while also sometimes pooping some of the parasites out.

Thankfully, both internal and external parasites are generally easy to treat in angelfish with cheap, easily to use products.

pH Levels!

Having the correct pH levels in your angelfish tank is very important as angelfish are very sensitive to changes in pH levels.

The ideal pH level for angelfish is between 6.8 and 7.2 but they can generally tolerate a slightly wider range of pH levels. The specific type of angelfish you keep will also come into play too so always double check the pH requirements for your specific angelfish as they can vary wildly.

One of the biggest problems that angelfish keepers face is a sudden drop in pH levels which can often be caused by things such as power outages or using tap water to fill up your tank.

Angelfish are very sensitive to these sudden changes in pH and it can often lead to death so it is always important to make sure that your angelfish tank has a stable pH.

You can use a variety of methods to maintain stable pH levels in your angelfish tank but we recommend using a quality aquarium buffer as this will help to keep your pH levels stable for longer periods of time.

Your Aquarium Is Too Small!

One of the most common problems that angelfish keepers face is simply having an aquarium that is too small.

Angelfish are not suitable for smaller tanks and they will often outgrow them very quickly. This can cause a number of problems such as your angelfish not having enough space to swim around or not having enough filtration to properly filter the water.

Some of the smaller species of angelfish can live in a 30 gallon tank but most angelfish species will need a larger tank than that. Unfortinatley, many of the people we see reaching out who are having issues with their angelfish dying have smaller tanks than this.

Poor Acclimatization To Your Tank!

If you’ve just added angelfish to your tank, it’s very important that you acclimatize them properly. This process can take up to an hour and involves slowly adding the angelfish to your tank so that they can get used to the new water conditions.

Many angelfish die each year because they are not properly acclimatized to their new tank and so it is always important to make sure that you follow the correct procedure.

Bacterial Infections!

Angelfish are also very susceptible to bacterial infections which can often lead to death. The most common type of bacterial infection in angelfish is known as columnaris which is a bacteria that attacks the skin and fins of your angelfish.

This bacteria can often be difficult to spot as it can look like your angelfish simply have a case of fin rot. However, columnaris is a much more serious infection and it can often lead to death if not treated quickly.

There are a number of different treatments for columnaris but the most effective one is using an antibacterial medication such as Kanaplex.

Aggression From Tank Mates!

Angelfish are generally peaceful fish but they can sometimes be aggressive towards other fish in their tank. This is usually only a problem if you have angelfish of different sizes in the same tank as the smaller angelfish can often become targetted by the larger angelfish.

This aggression can often lead to death so it is always important to make sure that you have angelfish of similar sizes in the same tank.

You can also use a divider in your tank to separate the angelfish if you are having issues with aggression.

Problems With Water Flow!

A less common problem with angelfish is issues with water flow but different types of angelfish need a very different water flow to each other. We will commonly see people keep a community tank with a number of different angelfish in it.

This can be problematic as the different types of angelfish in these community tanks may require totally different water flow rates to each other causing problems.

You really do have to check the preferred water flow rates for the types of angelfish that you keep. Thankfully, it is rare that issues with water flow levels will be enough to cause your angelfish to start dying by itself and there will often have to be other issues in the tank.

Fungal Infections!

Fungal infections are also relatively common in angelfish and they can often be fatal if not treated quickly. Some fungal infections can be contagious too so you may have to look to quarantine your angelfish if you do think that this may be the problem with your tank.

Thankfully, most fungal infections on angelfish are very easy to treat and you should be able to get the condition under control before you have any problems with your angelfish dying.

Ammonia Levels!

One of the most common problems that we see with angelfish is high ammonia levels in the tank. Ammonia is a toxic gas that is produced by the breakdown of fish waste and it can quickly build up to dangerous levels in an aquarium if not properly filtered out.

Angelfish are very sensitive to ammonia and so even small spikes in ammonia levels can often be enough to cause angelfish to start dying.

The best way to combat this problem is to make sure that you have a good quality filter in your tank that is capable of filtering out all the ammonia. You should also regularly test your water for ammonia levels and take action if you do see an increase.

Summary Of Why Your Angelfish Is Dying!

  • Genetic Issues In The Fish!
  • Low Quality Water!
  • An Unsuitable Diet!
  • Disease!
  • Stress And Anxiety!
  • Issues With O2 And CO2!
  • Problems With Parasites!
  • pH Levels!
  • Poor Acclimatization To Your Tank!
  • Bacterial Infections!
  • Aggression From Tank Mates!
  • Problems With Water Flow!
  • Fungal Infections!
  • Ammonia Levels!