Catfish Aquaponics – How Many Catfish Per Gallon Of Water?

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Last Updated on January 28, 2023

Catfish aquaponics has been on the rise in recent years. If you are struggling to know how many catfish per gallon of water to stock in your system, do not worry. This article will answer this question for you, and address many more.

The delicious catfish is one of the most rewarding fish you can raise in your aquaponics system. They are pretty forgiving and tolerant and they can survive in a wide variety of water conditions.

Knowing the stocking density of catfish will increase your chances of a better and more rewarding relationship between your plants and fish. So let’s dive into how many catfish can fit per gallon of water.

How Many Catfish Can Fit per Gallon of Water in Aquaponics?

Getting the correct stocking density for your catfish will help to go a long way in your aquaponics.

If the fish stocking density in your aquaponics system is low, there may not be enough nutrients to support the plant biomass. Conversely, if you have too many catfish, the filtration system (bacteria, plants, etc.) will not be able to adequately clean the impurities in the system and it may crash. This may in turn cause your catfish due to excess ammonia, and other critical water quality parameters to be out of the ideal range for catfish growth and health.

How Many Catfish Can Fit per Gallon

The appropriate number of catfish you can fit per gallon of water is one pound of fish per eight gallons of water. This way, stress is reduced and there’s adequate space for oxygen. However, note that when it comes to a fully grown catfish, you will require more than 8 gallons of water per fish.

Catfish are fast-growing fish and they usually grow quickly during their younger years. You can increase the quantity of water as your aquaponics system duration increases and the nitrifying bacteria get established.

Check out the Best Plants for Small Aquaponics and Where to Buy Fish for Aquaponics Systems

When it comes to catfish aquaponics recommended tank size, depends on the size of your fish. Catfish are fast growers and can grow up to 2 or 3 pounds in 12 months.

The fact that a whole 8 gallons of water are required for just one small-size catfish shows a large tank is required. Although, if you wish to raise one or two catfish and a small grow bed, you can make use of a small tank.

Go for a bigger tank so you can give your catfish a good quantity of filtration, aeration, and water flow and your catfish will flourish excellently.

Let’s take an illustration and see the ratio of a large tank to the number of catfish:

  • Let’s take 6 fully grown catfish weighing 2 to 3 pounds each. The total weight of all 6 grown catfish will be approximately 18 pounds. Therefore, a total of 18 pounds of catfish will require at least 144 gallons of water. (Using one pound of catfish should have 8 gallons of water).

Other Catfish Requirements

The tolerance and hardiness of catfish vary with species. Therefore, select the variety of fish that will suit and adapt to your aquaponics system.

Among the different species of catfish, channel catfish is one of the best varieties, the reason being that they are very forgiving and tolerant to cold water. They are perfect for beginners and they can as well live with other fish such as koi, tilapia, and crappie.

Other water quality requirements for your catfish to flourish in hydroponics include:

  • Dissolved oxygen: good air circulation and aeration is needed for your catfish. Ensure you use good air stones and air pumps so there is adequate availability of oxygen to suit your catfish. One amazing quality of catfish is that they can breathe air! This means that even if your air pump stops working, your catfish will not die because they will swim to the surface and breathe atmospheric oxygen. They will survive until you can come and fix the air pump and peace will be restored.
  • Food: feed your catfish with good high-quality protein fish food. You can also feed them with worms, black soldier flies, and insects. Ideally, we recommend you supply your catfish with about 2.5% of their body weight. Even though you can’t weigh your catfish weigh all your catfish, you can estimate their body weight from their sizes. A full-grown catfish weighs around 2 to 3 pounds. If there’s uneaten or excess food in your aquaponics system, you will need to readjust the amount of food the next time you feed your catfish. This will help to avoid waste and contaminating the system.

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  • Temperature and pH: catfish can withstand a variety of water temperatures. However, the ideal water temperature ranges from 65 to 90 degrees Fahrenheit. If the temperature goes above or below these standards, your fish will not grow optimally. You will need to stop feeding your fish (to minimize stress on the fish) until you can find a way to get the temperatures just right. They also have good tolerance to pH levels. Their pH can range from 7 to 8.

How Many Catfish in a Tank?

Generally, the rule for the calculation of how many fish can go into a tank is 1 inch of fish per gallon of fish. 10 percent of the water should be replaced with gravel where the fish can find a good hiding spot.

For example, a channel catfish tank size needs 8 gallons of water per fish. This means that you will need a large tank for bigger or more fish that you want to keep. 

How Many Gallons Does a Catfish Need?

15 pounds of catfish require about 120 gallons of water.

What Are The Best Catfish For Aquaponics?

Several different species of catfish can be used in aquaponics, with each having its advantages and disadvantages. This allows you to select the one that best suits your needs and your system setup. 

According to the Food and Agriculture Organization, the three best catfish that are grown commercially and grow best in aquaponics are Channel catfish (Ictalurus punctatus), African catfish (Clarias gariepinus) and the Brown bullhead catfish (Ameiurus nebulosus). Let us go into a bit more detail about these three aquaponics catfish.

1. Channel Catfish

Channel catfish can be stocked in high densities because they have a high tolerance for sibling densities. They are tolerant of cold water but grow faster at higher temperatures. Another advantage of using catfish in aquaponics is that they can live with other fish such as crappie, tilapia, and koi. So if you want to do a polyculture, it is the best candidate.

Channel catfish is one of the fastest-growing catfish and will grow very fast in your aquaponics system. They can attain growth rates of 3 pounds in just 12 months. This will ensure that you have a constant supply of plenty of fish to keep your system operating optimally.

2. African Catfish

The African catfish is another catfish species that is highly tolerant of sibling density. These fish can be stocked at high density and their growth will not be compromised. These fish can also tolerate a wide range of temperatures but grows best at higher temperatures.

African catfish are air-breathing. They are a great candidate for aquaponics systems because they can tolerate low dissolved oxygen levels in the water, so in the case where there is a power outage or something that results in a drop in the oxygen levels, your fish will survive for hours in those conditions. Even if a fish happens to jump out of a tank, the fish can survive until you can put it back in the water.

African catfish are very hardy fish and can withstand a wide variety of environmental conditions such as high ammonia. Growing this fish in your system will have low rates of mortalities.

A full-grown African catfish will reach a weight of 20 kg. This is provided that the ideal conditions are provided. It can grow up to 2 pounds in a space of 10 months. If the temperature of the water drops below 68 degrees F, the fish will stop growing so you will need to ensure that the temperature never drops below this.

3. Brown Bullhead Catfish

The Brown bullhead catfish can also be grown in aquaponics, although it does not grow as fast as the others. It also can survive some periods with no aeration in the water as long as the stocking density is kept low and the water in the tank is shallow.

These fish are benthic omnivores. They feed on insects, plants, worms, crayfish, and food pellets. Temperatures of 78 – 82 degrees Fahrenheit are ideal for these fish, and at this range, they will grow up to 1.10 pounds in two years.

Final Say – Catfish Aquaponics

Catfish are great fish to keep in an aquaponics system. These fish are heavy feeders, meaning they will provide sufficient waste that will be used as nutrients for your plants. They are also highly tolerant of sibling density, meaning that you can stock a lot of them in a single tank and they will continue to grow well. This limits the number of tanks that you will need for your system.

Tilapia used to be the most common fish grown in aquaponics, but catfish is also a good candidate. Whether you are a novice or an experienced fish culturist, the catfish is a good fish to try.

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