Angelfish Keep Dying: 4 Easy & Quick Solutions

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It can be frustrating to see that no matter how hard you try, your angelfish keep dying. When this happened in my tank, I investigated the issue pretty profoundly. Luckily, as time passed, I learned why it happens and how to fix it.

Angelfish usually keep dying due to inadequate water conditions, including pH, hardness, lack of oxygen, and temperature. However, new angelfish may die in your tank even if the water parameters are correct. This happens when the angelfish haven’t been acclimatized to their new environment.

This article will discuss what causes angelfish to die in fish tanks and how to acclimatize new angelfish, so they survive. If you are in a hurry, the first step would be testing the water pH, ammonia, nitrates, and nitrites, using the API Aquarium Test Kit (link to Amazon).

Also Read: Facts About Angelfish

Why Are My Angelfish Dying?

It is pretty standard for fish in an aquarium to die. In fact, the notion of losing a dozen or so fish to various factors every single year doesn’t bother most aquarists. However, it isn’t normal for multiple fish to die over a short period.

If your angelfish keep dying, you have to investigate. While fish can die because of many reasons, the number of factors that can cause them to expire quickly and in large numbers is small. They include:

1. Your Angelfish Were Sick When You Bought Them

This has to be your first consideration. If you got all your angelfish from a store, you have to consider the possibility that they were all diseased before you got them. Diseased fish are easy enough to spot:

  • They have physical signs such as rotten fins, missing patches of skin, fluffy growths, bloating, white specks all over their bodies, etc.
  • If you pay close attention to the tanks in the store, you will notice that the water is dirty, and a lot of the fish are either sluggish, completely inactive, or dead. It shouldn’t surprise you if the fish that came from such conditions died after adding them to your aquarium.

Sometimes, an aquarist brings a diseased angelfish home, and it proceeds to infect all their angelfish. Other times, they introduce diseases to their tank by adding plants, decorations, filters, heaters, and other infected items without cleaning them.

You also have diseases that thrive in a tank because of poor water conditions, not to mention infections that can hitch a ride on the food you feed your fish every day. Regardless of the source, a particularly virulent strain of a disease can infect and kill all your fish within a relatively short period.

Also Read: Angelfish Diseases

2. Inappropriate Acclimatization

Did you acclimate your angelfish? If all the dead angelfish are new, then you can comfortably conclude that the absence of proper acclimatization before you add them to the tank is the cause. In other words, you introduced your angelfish too suddenly.[1]

This is especially true for angelfish that come from dirty environments. The clean environment in your aquarium can place them all in a state of shock. The resulting stress is more than capable of killing them.

3. The Tank Wasn’t Properly Cleaned

Every aquarist is expected to keep their tank clean. However, thorough cleaning can harm your angelfish in the long run.

Massive and frequent water changes can cause drastic changes in the chemistry and temperature of the water. The resulting stress and shock will affect all the angelfish, and it could kill some or all of them.

Also, aquariums have good bacteria that prevent ammonia from building up by processing the angelfish’s waste. A thorough cleaning can destroy this good bacteria, especially if it involves replacing the biological filters. 

In a sense, your tank will behave as though it hasn’t been cycled. Cycling allows good bacteria that turn ammonia into nitrites (which are less toxic) to thrive in a tank. If you add angelfish to a tank that isn’t fully cycled, the poor conditions will kill them all.

Excessive water changes and irregular maintenance routines are normally driven by two primary factors, namely:[2]

  • Overstocking – On its own, overstocking can kill your fish. On the one hand, crowded conditions will induce stress. On the other hand, toxins like ammonia accumulate at a faster rate in small, crowded tanks. They force people to perform more extensive and frequent water changes to protect their fish from ammonia.
  • Overfeeding – Angelfish will keep eating if you keep feeding them. But this is very unhealthy because it attracts ailments like constipation, bloating, and swim bladder disease that can lead to death. If that wasn’t bad enough, overfed angelfish produces even more waste, causing the ammonia concentration to spike more frequently.

4. The Conditions aren’t Suitable for Angelfish

A tank with poor conditions can kill your entire population of angelfish. That includes:

  • The Wrong Water Parameters – Angelfish require precise parameters to thrive. If their aquarium has the wrong pH, hardness, and temperature, they will get sick and die. This won’t happen overnight. But if these insufficient parameters persist, you will lose your angelfish one by one.
  • Malfunctioning Hardware – The hardware in an aquarium can malfunction. For instance, if the heater misbehaves, it can either cook your fish or allow the temperature to fall far below the acceptable threshold. 

If the filter stops working, pollutants will saturate the water. If the filter’s output is too strong, the strength of the current will exhaust the angelfish. Any number of things can go wrong once your aquarium’s hardware malfunctions.

  • Inadequate Tankmates– Angelfish have an aggressive streak. If you keep them in a tank with the wrong tankmates, such as Tiger Barbs, Oscars, and other hostile cichlids, the resulting violence could kill them.
  • Stress– Various factors in a tank can generate stress. That includes overcrowding, overstocking, and the absence of plants and other appropriate hiding places. Fish cannot hide their stress. They tend to manifest symptoms such as frantic swimming, loss of appetite, excessive hiding, and glass surfing, to mention but a few.
  • Lack of Oxygen – Angelfish cannot survive in aquariums with low oxygen levels. They will succumb to hypoxia.
  • Lack of Food – A lot of aquarists go out of their way to avoid overfeeding. But underfeeding is just as problematic. If you fail to feed your fish, which can happen when an aquarist forgets or goes on vacation, they will die within a week.

Also Read: Signs Your Angelfish Is Dying

What to do if Your Angelfish Keep Dying?

If your fish were happy and healthy when they came from the store, but they keep dying, you can use the following steps to prevent additional deaths:

1. Adapting New Angelfish Properly

First of all, you should acclimate all your angelfish before you add them to the tank. You can do this by floating their bags in the tank for half an hour while also adding small amounts of water from the tank into their bags.[3]

This allows them to grow accustomed to the parameters in their new environment, not just the temperature but also the pH and hardness. You can also use the drip method, as described in the following YouTube video:

2. Putting Sick Fish in Quarantine

It would help if you kept all new fish in quarantine before you add them to the water. This gives you time to identify signs of any diseases and parasites they may have. You should also thoroughly scrub every object before adding it to the tank to prevent it from contaminating the water.

Follow the new fish for at least three days. If you notice signs of disease, such as sluggish behavior, change in color, or if they are hiding and not eating, you should consider keeping them in the quarantine tank where they can stay until they recover.

If your fish are sick, it is usually necessary to elevate the temperature by two to three degrees F and use aquarium salt to combat infections. I personally use the API AQUARIUM SALT (link to Amazon). Add one tablespoon for every five gallons of water. You should also consult a vet to pick the proper medication for your fish.

3. Adjusting the Aquarium for Angelfish

You cannot prevent your fish from dying unless you maintain the right conditions in their tank. That includes:

  • Cycling – This has to be the first step. Cycle your tank to completion. It takes a minimum of four weeks. I also suggest that you avoid cleaning your filter’s media. That may eliminate necessary bacteria.
  • Parameters – Maintain a temperature of 78 to 84 degrees F, pH of 6.8 to 7.8, and a hardness of 54 to 145 ppm.[4] The ammonia and nitrates should be around zero. These are considered ideal for angelfish.

To measure the pH, ammonia, nitrates, and nitrites, I use the API Aquarium Test Kit (link to Amazon). I love this kit because it lasts for hundreds of measures and comes with comprehensive instructions. All you have to do is look at the stripe’s colors, and you are good to go.

To ensure that the temperature remains stable, I use the Cobalt Aquatics Neo-Therm Pro Aquarium Heater (link to Amazon). Frankly, that is the only device that prevented this from happening.

For the water hardness, you can use the Premium Water Hardness Test Kit (link to Amazon). It is a terrific bundle that I recommend to everyone, especially if you are using tap water for your aquarium.

  • Filter – Your aquarium needs a functioning filter that produces a gentle current that is unlikely to exhaust the fish. I also recommend adding an airstone to increase the oxygen in your tank. I personally use the Hygger Aquarium Air Stone Kit (link to Amazon).
  • Food – Give your angelfish a balanced diet that includes flakes, pellets, small crustaceans, and worms. If you can’t use an automatic feeder, make sure you give them food they can finish in two to three minutes. They shouldn’t eat more than twice a day.
  • Tankmates – Keep your angelfish in tanks that have compatible fish with a friendly temperament and similar size. That includes Cory Catfish, Dwarf Gourami, Praecox Rainbowfish, and Platies, to mention but a few.[5]

4. Performing Routine Maintenance

Where maintenance is concerned, you have to keep the following in mind:

  • Water Changes – Perform small water changes of 5, 10, or 15 percent every week. You can perform more extensive water changes of up to 50 percent once a month.[6]
  • Conditioners – Use water conditioners to remove toxins that you usually add to an aquarium during a water change, such as chlorine and copper. You can also use conditioners to alter the pH and hardness, not to mention removing ammonia from the aquarium in situations where the fish are too weak for you to perform a water change.

What to do if Your Angelfish is Dying?

If your angelfish is dying, follow the steps below to save it:

  1. Place the angelfish in a separate tank with a temperature of 78-84 degrees F and a pH of 6.8-7.8.
  2. If the fish looks dirty, clean it. That includes removing the dirt and wiping any obstructions you can see off the gills.
  3. If the gills look like they are stuck together, you can stroke them to free them.
  4. Make sure the water in the new tank is well-oxygenated. Add an air stone or pump pure oxygen directly into the water.
  5. You can use products such as methylene blue (or Maracyn Two) to fight fungal infections and illnesses like fin rot.
  6. You can fight Ich by raising the temperature by a few degrees and treating the fish to a salt bath.
  7. If you can see parasites (like anchor worms) sticking out from the angelfish’s body, you can use tweezers to remove them

As a rule of thumb, if you suspect that your angelfish is sick, I suggest consulting a veterinarian. By asking an expert, you’ll know what remedy to use. It is pointless to treat angelfish with products that won’t necessarily work.

Why do my Angelfish Fry Keep Dying?

Angelfish fry will die for any number of reasons, including:

  1. Angelfish fry are more sensitive to poor parameters and can die if the pH, temperature, or hardness are inadequate.
  2. A failure to perform regular water changes will introduce a chemical imbalance, and the accumulation of ammonia may kill angelfish fry.
  3. Angelfish fry can die if they are exposed to too much light. 10-12 hours should suffice.
  4. Angelfish fry shouldn’t be kept in community tanks, or adult fish will eat them.
  5. Young angelfish will die if you overfeed or underfeed them.
  6. Angelfish fry may die due to stress, secondary to hostile and energetic fish, loud sounds, and strong currents.

If you wish to raise angelfish fry, I highly suggest reading an article I wrote on how to keep angelfish fry alive in seven simple steps. These will give you insights into how to grow these delicate creatures.

Also Read: Are Angelfish Difficult To Keep?


Angelfish are beautiful, easy to keep, and relatively cheap. But they are not invincible. Many times, they fail to survive, despite your best efforts. Most of the time, the cause of death remains obscure.

If that is your case, I suggest checking the water parameters. That includes checking the pH, temperature, ammonia, and hardness. Also, when getting new angelfish, make sure that you acclimatize them properly.