Ideal Cory Catfish pH Level (& How To Change It)

Last Updated on 2023-05-24

The Cory catfish, or Corydoras catfish, is a jovial, well-tempered fish. Like all pet fish, this breed, too, has certain demands that must be met. If your pet Cory’s strict requirements are not heeded, it may fall ill, refuse to breed, or, in extreme cases, face death. These requirements include maintaining the ideal Cory catfish pH level

A tank’s pH level is subject to change and can fluctuate when there are changes in the environment. For example, when new fish are added to an already populated tank or plants and decorations are placed inside, the water’s pH level is bound to change. 

Without the right water pH range, Corydoras will suffer. Luckily, this guide will tell you everything you need to know about maintaining the correct pH level for your pet, Cory catfish. 

What is the Ideal Cory Catfish pH Level? 

The ideal pH level for your Cory catfish is between 7.0 to 8.0. However, some varieties of Corydoras need a slightly lower pH. For example, emerald Cory catfish can survive in a pH as low as 5.5 and even thrive at 8.0. 

To stay on the safe side, though, the ideal Cory catfish pH level is between 7.0 and 8.0 for Cory catfish bred by man and 5.5 to 8.0 for wild varieties.  

What Happens if the pH Level Is Too High? 

A high pH level can have a significant impact on your fish. When the water’s pH is too high, it can cause serious damage to your fish’s gills, eyes, skin, and scales. They may also lose the ability to get rid of metabolic waste and die as a result of toxic build-up within their bodies. 

High pH can seriously tamper with the lifespan of your Cory catfish and cause them to die within just a few hours. However, this happens if the pH is too alkaline; a slight variation is okay, as long as it goes back to the standard range soon. 

What Happens if the pH Level Is Too Low? 

A high pH level can be detrimental to your fish’s health; in the same way, if your tank’s water is too acidic, your Cory catfish will suffer, too. 

An extremely low (acidic) pH level will interfere with your pet fish’s reproductive cycle. They will be unable to produce eggs or hatch new fries. Your fish may even stop breeding altogether.  

In some cases, the fish may begin to produce excessive mucous. This makes it harder for fish to breathe because of the mucous clogging their gills. As a result, your Cory catfish may die. 

Fish can also begin to feel extremely stressed out by the change in pH levels; this can lead to stunted growth and trouble producing eggs. Some of your Cory catfish may not experience stress, but others might. It depends on the individual fish. 

(Find out about 12 more great aquarium catfish.)

corydoras aeneus - bronze catfish close up | check out those… | Flickr

How to Lower The pH Level In The Tank 

Luckily, there are ways to make sure your tank’s pH level stays just right. Here are some ways in which you can lower the tank water’s pH level: 

Use Driftwood 

A quick, easy, and natural way to lower pH levels in your tank is by adding driftwood. Driftwood releases tannic acid into your tank’s water, which then naturally reduces the pH level of the tank.  

You can easily find driftwood make specifically for water tanks in your local pet store or online. This is important because these pieces of driftwood have no chemicals or preservatives, so they won’t harm the fish in your tank.  

You can also choose to use driftwood made for reptile tanks as these are also free from chemicals. However, these pieces of driftwood aren’t heavy and may need to be weighed down so that they don’t float in the water.  

Add Live Plants 

Plants can bring down your water’s pH level. This is because they release carbon dioxide, which then dissolves into the tank water, making it more acidic. Luckily, carbon dioxide will not create a very strong acidic environment. Instead, it will tamper with the pH levels just enough to make sure you reach the perfect level. 

Plants can also improve the tank’s general atmosphere by making it look good and giving your catfish a place to lay their eggs. 

Add Peat Moss 

Peat Moss is another great way to naturally reduce the pH level in your water tank. However, it requires a bit of preparation. First, it’s important to find peat moss designed specifically for use in water tanks because this kind is free from chemicals.  

Once you have the peat moss, it’s important to soak it in a bucket of tap water for 3 to 4 days. If you skip this step and place the peat moss directly into your tank, it may turn the water yellow or brown.  

After you’ve soaked the peat moss, do not add it straight to the tank because it will float and will then be unable to reduce pH levels effectively. Instead, purchase a filter bag or make your own bag out of nylon material. Transfer the peat moss into the bag and place the bag in the tank.  

Other Methods 

These are a few other simple steps you can use to reduce pH levels: 

  • Add a few almond leaves to your tank. The leaves may turn yellow over time, but this only means that they’re working to reduce pH levels.  
  • Get a reverse osmosis filter that will purify your water.  
  • Try changing your filter or cleaning it regularly so that debris and bacteria don’t gather in the filter.  

Just as there are ways to lower the tank’s pH level, there are many options that can help you raise it, too. 

File:Corydoras sp. CW010.jpg - Wikimedia Commons

How to Raise the Tank’s pH Level 

Use Baking Soda 

Some people use baking soda to raise the water’s pH level. Baking soda is an excellent alkalizing agent and can make the tank’s water more alkaline without harming your fish. 

If you plan on using baking soda to raise your tank’s water’s pH level, all you have to do is keep adding the power until you reach the desired pH level. Consider using a teaspoon to add the soda; if you accidentally slip and pour in too much powder from the sachet, you risk raising the pH too much. 

Keep testing the water’s alkalinity with a pH meter, or a universal indicator strip. Also, ensure that there are no fish inside your tank as you add the baking soda powder into the water. While creating the ideal pH level solution, store your fish in a temporary container with clean water. 

Wait half an hour after adding the baking soda to make sure it has dissolved thoroughly, then add your Cory catfish back in. 

Change The Substrate 

The substrate of your water tank refers to changing the material that forms the bottom layer of the tank. Most often, a water tank’s substrate is gravel or fresh marble. If you wish to raise the pH level of the water in your tank, you can change the substrate to coral or limestone instead.  

Cover the bottom of your tank with crushed coral or limestone. Ensure that you use enough material to make the substrate at least 1 inch thick. If you’re worried about where to get crushed coral or limestone, don’t be. They’re readily available in most pet stores. 

The process of changing your tank’s substrate can get quite dusty. Hence, it’s important that you remove your fish from the tank first and then change the substrate. Otherwise, you can harm your fish.  

Changing your tank’s substrate is a very effective way of raising the pH levels of the water. In most cases, you can see results in just one week.  

Other Methods 

Here are a few other methods you can use: 

  • Add seashells. These contain carbons that will raise the pH level of your tank. 
  • Remove any driftwood you may have in the tank, as this lowers pH levels.  
  • Use dolomite chips. These stones naturally raise the pH levels of water.  
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As you can see, there are many ways in which you can successfully alter the water’s pH level. It is vital that you keep checking the tank’s pH level; if the water is too acidic or alkaline, your fish will suffer. 

To raise the alkalinity, try using baking soda or adding seashells. If you wish to lower the pH levels and make the tank water more acidic, opt for carbon dioxide injections, aeration, or live plants. 

Just make sure to check the pH level after trying out their methods to make sure you have achieved the ideal Cory catfish pH level of 7.0 to 8.0, which will help keep your catfish healthy and happy! 

If you have any of the following fish, then you can also find out about the pH levels they need too: angelfish, cardinal tetras, gouramis, guppies, and mollies.

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