Aquaponics systems commonly involve raising freshwater fish because they can tolerate diverse water temperatures and pH…
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If you grew up fishing in the rivers, ponds, and lakes around North America, then chances are one of your first encounters was with the mighty catfish. Also, commonly found in the form of tasty deep-fried nuggets, the catfish has natural talents that extend far past the dinner plate. In fact, catfish are reliable breeds to use in an aquaponics setup due to their adaptability to a wide range of living conditions. It’s safe to say that caring for catfish in aquaponics systems is a breeze compared to other fish breeds.
In this article, you will learn some important tips on how to raise catfish in an aquaponics setup.
Why Raise Catfish in Aquaponics Systems?
Catfish frequently top the list of best aquaponics fish for many reasons, including that they’re often locally or regionally sourced, unlike many other breeds such as carp or trout. They are also edible, allowing you to consume the fish as well as use them to provide nutrients to the system.
Another reason to raise catfish in an aquaponics system is that they’re not territorial and can easily be mixed with other species. This becomes helpful when you plan to keep heterogeneous species of fish inside your system.
There are three main catfish types that you can use in aquaponics, and they are:
- Eel-tailed – a bottom-feeding omnivore native to eastern Australia’s freshwater habitats.
- Channel – the most popular catfish used in aquaponics because they’re relatively cheap and they grow fast. They prefer warm temperatures but can still tolerate cool water. They can be found in rivers, streams, lakes, and ponds in Canada’s Hudson Bay and even in Colorado.
- Brown Bullhead – this catfish type is widely distributed in North America. They tend to mature slowly, but they are tough.
Requirements for Caring for Catfish in Aquaponics Systems
Below are the requirements of a healthy and thriving catfish aquaponics setup.
The recommended catfish stocking density is one pound of fish for every eight gallons of water.
Since catfish grow long and tend to get bigger fast (approx. three pounds in one year), you will need a fairly large tank with a diameter of at least 4ft. The tank size will also depend on the size of your grow bed. For example, based on the stocking density above, if you plan to keep three catfish with a total weight of nine pounds for your small grow bed, then you should plan to have a 72-gallon tank at a minimum.
The ideal temperature for raising catfish in aquaponics is between 65 and 75 deg F. Catfish are generally sturdy species that can survive different climate conditions. However, it is worth noting that cold temperatures will decrease metabolism and food consumption. This results in lower nutrient availability for plants, which consequently affects the efficiency of your setup.
Sunlight can be beneficial for the catfish because it warms up the water, which the fish enjoy. However, catfish also like to hide, so it would be a good idea to provide some form of shade in the tank.
Freshwater catfish will thrive in water pH levels between 5.0 and 7.0
Catfish need at least 5mg/L of dissolved oxygen concentration. Anything higher is ideal.
Best breeds for aquaponics
As mentioned, channel catfish are the most popular choice of catfish to care for in aquaponics. Just like tilapia, channel catfish can do well in the heat. However, compared to tilapia, channel catfish have better chances of surviving and doing fine in cold water, even if temperatures fall below 70 deg F.
Fish diet/nutrient requirements
Catfish require high-protein foods, and if you want more sustainability, you can raise your own worms as catfish food. Pellets made for catfish are also available, and they can be given to your fish as well.
You can feed catfish three times a day as much as they can eat in five minutes. However, after feeding remember to remove any leftover feed.
How to clean the tank
Catfish are great for tanks because they eat algae and help clean the tank for you. However, this doesn’t mean you don’t have to clean the tank yourself. It is recommended that you change 10-15% of the water once a week, and in this case, it’s better to use a siphon hose. Algae scrubbers or scrapers can also help with your maintenance.
Bacterial infections are largely a problem for the catfish industry in the U.S. One of the most common bacterial infections to look out for is enteric septicemia of catfish (ESC). This fatal infection is caused by the bacterium Edwardsiella ictaluri, and channel catfish are their primary targets.
Rashes on the body, bloody spots on the fin, and head ulcerations known as “hole in the head” are just among the signs of ESC infection. Maintaining excellent water quality and ensuring your fish are not under stress is the key to preventing ESC in the first place.
Aquaponics plants best suited for
Some of the plants that you can grow successfully with catfish are pomegranates, citruses like oranges and limes, dill, and watercress. However, there is a wide variety of plants that will also successfully thrive.
When to rotate fish in and out of the tank
In about six months, given the right conditions, you can have a full-grown catfish ready to be harvested. You can then start with about 40 fingerlings in your tank and let them grow out of it.
An ideal tank filter should be able to process water 3-5 times in an hour. Ensuring your water filtration system can keep up with the amount of waste in the tank can help you have full-grown catfish in just about six months.
Can they be mixed with other breeds?
Catfish have been known to coexist with tilapia, koi, and crappie.
It is ideal to have fine gravel at the bottom of your fish tank to achieve murky water if you plan to breed catfish. Some spots for hiding will also help as catfish like to hide when breeding. You can place three females for every two males in the tank; the more catfish, the more chances of successful breeding. To encourage spawning, ensure that water temperature is between 75 and 80 deg F.
Just like bluegill, catfish will build nests, where the females lay the eggs. The males then spray the eggs with sperm to fertilize them. They will then guard the eggs until they hatch, which is about 10 days later. Unlike bluegill, however, cannibalization won’t take place. In fact, the male will continue to guard the fry until they are a week-old.