Taking care of your cory catfish is relatively simple, but it’s always important to maintain water parameters. Doing so will help your fish live longer and avoid common illnesses and diseases.
Cory catfish need water temperatures from 70-82 F, a pH of 6.0-8.0, and water hardness ranging from 5-10 dGH. Keeping your tank within these parameters creates ideal conditions for your cories to survive
As with any fish, a good understanding of how to set up your tank and maintain it goes a long way.
Keep reading, because I’m going to provide helpful information, including a detailed chart, with all the water parameters you need to keep an eye on. I’ll also provide some information from my personal experience with cory catfish to help you identify and correct problems before they get out of hand.
Table of Contents
What Tank Conditions Do Cories Need?
Cory catfish are widely considered to be an easy fish to care for, but that doesn’t mean you can sit back and let the tank care for itself. Fish ownership is an active process, and it’s important to monitor your tank regularly to make sure it’s within optimal parameters.
For cory catfish, you’ll want to adhere to the following table to keep your tank in check:
| Temperature Range | 70 – 82 F |
| pH | 6.0 – 8.0 |
| Minimum Tank Size | 10 gallons |
| Water Hardness | 5 – 10 dGH |
| Ammonia | 0 ppm |
| Nitrites | 0 ppm |
| Nitrates | Under 40 ppm |
These 4 factors are the most common indicators that your tank is perfect for housing cories, and the key with each of these parameters is stability. A cory catfish can survive in slightly acidic or slightly alkaline water, for example, but they will suffer immensely if the pH fluctuates often.
How to Choose Your Tank Size
Cories need at least 10 gallons or more, but if you’re putting them in a community tank, it’s much more likely you’ll need a tank 30 gallons or more.
Your tank size is one of the most important water conditions, as a tank that is too small will almost always suffer from high ammonia and nitrite levels, among other detrimental conditions. Picking a tank that is appropriately sized for the fish you want to keep is the first and most important step to being an ethical and mindful aquarist.
The 1 gallon per inch of fish is pertinent, but it’s not a hard and fast rule. Remember, cories get up to 4 inches and like to be in shoals of 6 or more. That math alone should encourage you to carefully consider your options.
If your tank is overstocked, it’s important to reduce the number of fish by either moving them to a larger tank or splitting your fish between two tanks.
How to Test Your Water Parameters
Testing your water parameters is simple; just rely on a test kit like this API test kit. It tests for ammonia, nitrites, nitrates, and pH.
To test any of these parameters, follow these steps:
- Dip the vial in the tank to get a sample of aquarium water.
- According to the package instructions, drop the appropriate number of drops into the vial corresponding to the parameter you are testing. API test kit has different droppers for pH, nitrates, etc…
- Seal it with the cap.
- Shake the vial for the time indicated on the instructions.
- Read the color coded chart on the API test kit to determine the condition of your water.
Testing for hardness follows the same principle. Purchase this API GH and KH test kit and follow the instructions on the label.
If you want to test your temperature, you can rely on a simple thermometer or thermostat. I recommend the Via Aqua Quartz Heater. Not only does it offer you the ability to adjust your tank’s temperature as needed, it provides a simple stick-on thermostat that you can read at any time to make sure your tank’s temperature is within acceptable ranges.
Testing is simple and takes a matter of minutes. Test your parameters weekly to make sure that your tank is stable.
How to Maintain Temperature
Keeping your tank between 70-82 F is crucial for your cories. They are quite hardy in a range of temperatures, but if you want to keep other fish 75-78 F is usually considered the golden standard of freshwater aquarium temperature.
Lowering the Temperature
In the event of a sustained heatwave, you will need to take active steps to lower the temperature in your aquarium. That includes removing the lid, turning off the lights, floating ice packs, and blowing a fan across the surface of the water.
You can also do a water change of 30-50% to immediately cool the water. Remember, anything above 82 F is unpleasant for most tropical fish.
To avoid sustained heat exposure, keep your fish tank out of direct sunlight. Not only does this gradually raise the temperature of the tank, it will also encourage significant algae growth beyond normal levels.
Raising the Temperature
Raising the tank temperature necessitates a heater in most cases. The submersible Via Aqua Quartz Heater is a great example. You’ll need to monitor your tank carefully during the winter.
The room temperature will affect the temperature of your tank, and in cold conditions, your fish are more susceptible to lethargy, reduced appetite, and increased stress.
How to Maintain pH
The pH scale measures whether something is acidic or basic. Anything below 7 is acidic, and anything above 7 is considered basic. When a tank is too acidic or too basic, it can affect the health of your fish. Different fish are capable of handling different pH levels. Cories are quite sturdy, capable of handling slightly acidic or basic pH.
Generally, you don’t need to actively manage your pH unless it falls outside of the 6.0-8.0 range, or if the pH is fluctuating wildly. The reasons for pH fluctuations can be complex and multifaceted.
More activity in the tank can cause an increase in pH, while a change in mineral content, whether through newly introduced substrate or tap water, can decrease pH. Remember to test for pH regularly to ensure your tank is thriving.
Raising Your pH
To increase your pH, you can perform more water changes and aerate your tank with an air stone. There are pH adjustment kits available, but they should be used sparingly and with caution.
Lowering Your pH
Adding driftwood can lower your pH. That’s because driftwood naturally releases tannins into the water, a beneficial chemical compound that is slightly acidic. Pumping CO2 into a tank can also lower the pH, as when CO2 dissolves, it produces a slightly acidic compound: carbonic acid.
How to Maintain Water Hardness
Water hardness is the black sheep of tank parameters, since many aquarists recommend you don’t fiddle with it at all unless it’s way out of line. It is, in essence, the measure of calcium and magnesium in your tank, and too much or too little can be detrimental.
In the majority of cases, water hardness will not be a make-or-break parameter that you need to closely monitor. You can test your hardness levels with a test kit. Soak dechlorinated tap water in peat moss, almond leaves, or driftwood to decrease the hardness of your water. To increase water hardness, you can use reverse osmosis water or remineralization products like Seachem Equilibrium.
How to Keep Nitrates Under Control
Nitrates are the end product of the nitrogen cycle, and keeping them in check is a common beginner concern.
The nitrogen cycle goes from ammonia > nitrite > nitrate. The harmful ammonia prompts the growth of bacteria that can break it down, which thus prompts the growth of nitrate. Because there’s nothing to consume or break down the nitrate, it will build up over time.
That’s where water changes come in. Diluting the water reduces the nitrate concentration. Aquarists differ on how often you need to water change, as it greatly varies based on how well your fish tank is stocked and how large the tank is.
You may need to water change up to 50% weekly or 25% bi-weekly. To simplify, nitrates over 40 ppm can be harmful, so conduct water changes regularly to keep your tank under this threshold.
How to Keep Ammonia and Nitrites Under Control
Ammonia is the ‘starting point’ of the nitrogen cycle. In order for the tank to be habitable, it must be free of ammonia, a strongly basic compound. Ammonia is produced as a byproduct of fish waste and leftover food. If your nitrites, then nitrates, are not up to the task of dealing with the ammonia production, your fish will be detrimentally affected.
Ideally, your ammonia and nitrite should be at 0 ppm at all times. If your nitrite (not nitrate) levels are spiking, it’s likely a product of a recent ammonia spike. Overfeeding, weak filtration, poor water flow, and waste buildup will cause ammonia and nitrite levels to rise, both of which can be harmful–even deadly–to your fish.
FAQs
How Can I Tell If My Water Parameters Are Off Balance?
Aside from testing, your fish will be the first to tell you if your parameters are off. Fish may exhibit behaviors of stress and lethargy, as they are more susceptible to ammonia poisoning, fin rot, and other conditions, diseases, and parasites.
How Many Gallons of Water Do Cories Need?
Cories need a minimum of 10 gallons of water to survive, but if you are keeping them in a larger group or with a community tank, upwards of 30 gallons might be preferable.
Conclusion
Cory catfish are hardy, peaceful, and very simple to care from. The key, as with most fish, is a recognition of what they need and stability. Keep your tank conditions stable with constant monitoring, and your cories will live a long and happy life.
Be sure to refer to the handy chart above to see exactly what conditions are best for your cory catfish.
