Do Angelfish Like Hard Or Soft Water?

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When I was new to fishkeeping, I had no idea about the different kinds of water available for fish. However, as I saw my angelfish frequently don’t survive, I got more into the conditions they require.

Then I was introduced to the terms’ hard’ and ‘soft’ water. Do angelfish like hard or soft water? Can I merely use tap water for my angels and expect them to survive? Let’s dive right into it.

Angelfish like slightly soft, acidic water. Therefore, aim for a degree of hardness between 0 to 6 (0 to 100 for the ppm). You may use reverse osmosis or water pillows to soften your water. However, keep in mind that drastic changes in pH and minerals may harm your angelfish.  

Later in this article, I will show you a few useful techniques to achieve soft water for your angelfish. Also, I will mention a few scenarios in which you are advised to leave things as they are, even if the water is relatively hard.

Do Angelfish Prefer Hard or Soft Water?

As we move forward, I will elaborate on the differences between the two types of water conditions. However, if you’re wondering where angelfish fall in this discussion, they prefer soft water. 

Hard water fish include species like guppies, platies, scats, archers, mollies, and the like. Then again, this is probably going to create confusion among beginners, that have heard of fish owners placing angelfish and mollies in the same tank.

How can these two species share a tank when one of them prefers soft water while the other one has an affinity for hard water? 

The answer is simple. Angelfish prefer slightly soft, slightly acidic water. However, they are hardy creatures that are more than capable of surviving in much harder water. This is especially true for the angels that you buy in a store. 

Because they were commercially bred, they probably spent the first few stages of their lives in harder water than you usually find in their natural environment. As such, they will thrive in your community tank even if the hardness of the water exceeds their preferred range. 

Of course, some fish owners will tell you that, while their angelfish have survived in hard water, they do not breed successfully. This makes some sense. Angelfish eggs are less likely to hatch in water whose parameters are less than ideal. 

If the water in your tank is too hard, the angels might survive, but their eggs and fry will probably die. Also, it may lead your angelfish into hiding, presenting radically passive behavior. If you’ve noticed this in your angels, I highly recommend that you take a look at it to solve that issue.

This is a perfectly acceptable outcome for people who don’t want their angels to spawn.

But what about fish owners who wish to rear angelfish fry for personal or commercial purposes? What should they do in such situations? First of all, you should first consider the source of water.

Also Read: Angelfish Water Parameters

1. Tap Water For Angelfish

Most fish owners get water for their tanks from the tap because it is easily accessible. Tap water is, for the most part, safe. That being said, it is unpredictable. Tap water is not all the same. The pH, GH, and KH will vary depending on your location.[1]

This is why, as mentioned above, some experts encourage new fish owners to find species that fit the hardness of the water available to them.

They know that some places have naturally harder water than others and that it is more convenient to find species that are compatible with the readily available water. 

You are free to use tap water if its parameters are suitable for your angelfish. If they vary too drastically, find a different water source.

If you have decided to use tap water, get a de-chlorinator. It will remove the chemicals that were used to treat the water to make it safe for human consumption.

2. Bottled Water

Bottled water is just as unpredictable as tap water. It has a lower pH, but the mineral content will vary with each brand. Pay close attention to the labels.

Better yet, experiment with as many brands as possible until you find one whose hardness and pH are appropriate for your angelfish. 

When you do so, try a single type for an extended period. If you keep on switching between brands, you won’t know which one has performed best for your angelfish.

Also, this goes without saying, don’t use distilled or flavored water. It will hasten bacteria’s growth, and your angels aren’t likely to survive. 

3. A Body of Water 

Some people get their water from a local water body such as a lake or creek. This isn’t a good idea because you have no way of knowing how polluted the water might be. You must also account for the mineral content. Local water bodies are too risky.

How Can I Soften The Water For my Angelfish?

All of the above assumes that you have the option of finding a water source that is soft enough to accommodate your angelfish.

Some people don’t have access to soft water. Fortunately for them, you can soften water using methods such as the following:

1. Reverse Osmosis

Reverse osmosis involves forcing a concentrated solution through a membrane such as Cellulose Triacetate and Thin Film Composite by applying pressure to it.

When utilized appropriately, a reverse osmosis unit will remove heavy metals, minerals, and even contaminants. 

But using reverse osmosis to get the water to the right hardness is complicated. You risk taking too many metals and minerals out of the water or too few.

However, if you are interested, I personally use the Aquatic Life RO (link to Amazon). It is mostly suitable for relatively large tanks, with a decent amount of fish and vegetation. 

2. Water Pillows

Water-softening pillows are devices that can be installed in tank filters; they are used to strip water of minerals and heavy metals as it passes through the pillow softeners. However, the downside here is that it doesn’t stay in the water forever. 

Usually, a pillow lasts for about five charges. Then, you will have to replace it and purchase a new one. However, the price is pretty low and hovers around five dollars.

If you are interested, here is the API Aquarium Filtration Media (link to Amazon). I haven’t personally used it, but it has received excellent reviews. 

3. Consider Rain Water

While local water bodies are not appropriate sources of tank water, the same cannot be said for rainwater, which is pure enough to cater to the needs of your angels. When it comes to catching and storing rainwater, be sure to use a clean and sterile container. 

Also, you should consider the air pollution in your particular area. In case your city is known for having polluted air, perhaps you should avoid using raindrops.

Eventually, ensure that the water has been poured directly into your container (without meeting a rooftop or a treetop beforehand). 

4. Try a Peat

If you place peat in the filter of your angelfish tank, the water will flow over it, becoming softer in the process. You can also soak peat in buckets of water for a week or two before transferring it to the tank.

Either approach works. Don’t forget to remove contaminants by boiling the peat beforehand. You are also encouraged to look for peat that doesn’t have additives. If everything looks okay, you are good to go.

5. Driftwood

If you have small pieces of driftwood, boil them. If you have large pieces, pour boiling water over them; allow the wood to cool before scrubbing it, after which it can be added to the tank.

While not as effective as the methods above, driftwood will soften your water, not to mention releasing tannins that stain the water.

If the water is too soft, you can add crushed coral to make it harder. Place the coral in the filters or use it as the substrate.

Limestone can also help. Besides making your tank look cool, it will cause minerals like calcium to leach out. A more direct approach involves adding buffers that manipulate the GH and KH without changing the pH. 

What to Consider When Softening The Water For Angelfish

While the notion of softening your water to accommodate your angelfish sounds appealing, you should keep the following factors in mind:

First of all, soft water is more unstable than hard water as far as the pH is concerned. This is why some fish experts encourage you to let your angelfish acclimate to hard water. By attempting to soften it, you could cause changes in the pH that are so rapid they cause harm. 

  • Angelfish, like most fish, are not fans of rapid changes in the pH. Unless you know what you’re doing, don’t mess with the hardness of your water.

Also, regardless of whether you’re using reverse osmosis filters or collecting rainwater, the process of turning hard water into soft water consumes a lot of time and energy. Keep this in mind before undertaking the task.

Moreover, even though some fish like soft water, filter bacteria need hard, alkaline water. Water that is too soft and acidic will render them ineffective. Keep that in mind before softening your water.

The takeaway is this: soften your water to accommodate your angelfish if you think that the change is necessary for your fish to live healthy lives. But if your angels are showing no signs of ill health or distress despite the hardness of the water, leave the water alone.

What Are The Differences Between Hard And Soft Water?

The water chemistry of your aquarium is vital to the health of your angelfish. Everyone understands the importance of maintaining the right pH and temperature, not to mention removing nitrates and ammonia.

But few people, especially beginners, consider the hardness. Do angelfish prefer hard water or soft water? To answer that question, you must first understand what the terms’ hard water’ and ‘soft water’ mean.

When people talk about the hardness of water, it is generally about the volume of minerals that have dissolved in the water. When measuring the hardness of water, you can look at the General Hardness (GH) or the Carbonate Hardness (KH). Both of them are important. 

GH is concerned with the magnesium and calcium that have dissolved in the water. KH is concerned with the carbonate and bicarbonate ions. It is also called the alkalinity. This is because it affects the pH of the aquarium.

A high KH will create stability in the pH, which is suitable for your angels. A low KH will do the reverse. Hence, people who are struggling to bring their pH under control should investigate the carbonate hardness of their water. 

Water is soft if the degree of hardness ranges from 0 to 6 (0 to 100 for the ppm). Water is hard (or slightly hard) if the degree of hardness ranges from 6 to 25 (101 to 499 for ppm).

Water is very hard (so-called liquid rock) if it has a degree of hardness that exceeds 30 (450 in ppm).[2]

There is such a thing as hard water fish and soft water fish, that is to say, fish that thrive either in hard water or soft water. Soft water is found in regions like West Africa, South America, and Southeast Asia where rivers flow across terrain that doesn’t have much in the way of soluble minerals. 

The fish that live in such rivers are accustomed to hard water, and the individuals who choose to domesticate them are encouraged to replicate these conditions in their tanks. The same is accurate for species whose natural habitats are bodies of hard water. 

If you are starting from scratch and you are looking to populate your aquarium with fish, you are encouraged to prioritize the fish whose bodies can thrive in the type of water commonly encountered in your area.

In other words, if your water is hard, you should get hard water fish. Soft water calls for soft water fish.

Also Read: Best pH Level For Angelfish


Angelfish typically lean to slightly soft, acidic water. However, there is a good chance they are accustomed to hard water, especially if you’ve purchased them from a pet shop. That is because angels are adaptable and are relatively hardy.

Hence, if you experience no troubles in your tank, you shouldn’t switch to soft water. Keep using the water source, which works best, even if the water is hard. Keep in mind that softening the water may harm your angels, especially if the pH changes are sharp.

I hope my article has shed some light on whether or not angelfish like soft or hard water. The bottom line here is not to make drastic changes. If your angelfish survives, you are probably already doing the right thing.