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While many beginners set their sights on raising tilapia themselves and becoming completely independent from the commercial fishery supply chain, one commonly overlooked item is how to populate tilapia holding tanks the right way. The good news is that, in general, if you maintain good water quality, feed them consistently, and sustain optimal pH levels, then half the battle in raising quality stock is already won. However, understanding the tilapia to water tank ratio is also critical if you plan on achieving long-term success.
Generally, one pound of tilapia needs three gallons of water. While they can grow bigger, a full-grown tilapia often weighs about one pound. Meanwhile, to satisfy the oxygen requirement of 100 pounds of tilapia, you need a flow rate of 6 to 12 gallons per minute. In terms of the length-width-depth ratio of tanks, it should be 30:3:1 to achieve good flow patterns. For circular culture tanks, their sizes usually range from 12 to 30-feet in diameter with 4 to 5-feet depth.
Tank Culture of Tilapia: The Basics
Water temperature is a crucial factor when culturing tilapia in tanks. To achieve maximum growth of tilapia, the temperature range should be from 82 to 86 degrees Fahrenheit. For temperatures below 54 degrees Fahrenheit, tilapia will no longer have resistance to diseases. They become prone to bacterial and fungal infections. At temperatures below 50 degrees Fahrenheit, the tilapia will most likely die.
In terms of tank materials, concrete and fiberglass are the most durable. You should ensure that the tank material is not toxic or corrosive. To promote cleaning and decrease resistance to flow, its surface must be smooth.
While there are different tanks available, circular and regular tanks are the most common. Because they’re self-cleaning, circular tanks are the most well-recognized tank to use. Meanwhile, rectangular tanks facilitate poor flow — with incoming water flowing directly to the drain and getting other parts of the tanks stagnant, lowering oxygen levels. Thus, for tilapia culture, circular tanks are better than rectangular ones.
What Is the Correct Ratio of Fish To Water?
An inch of fish generally needs one gallon of water, but you can only do it for smaller fish and tanks. As some fish grow bigger, you need to consider the pounds to determine the right ratio. For tilapia to water ratio, the general consensus is three gallons of water for every pound of fish.
How Many Tilapia Can Go in a 100-Gallon Tank?
Given that the widely accepted tilapia to water tank ratio is 3 gallons of water for every pound of fish, only about 33 or 34 tilapia can go in a 100-gallon tank. If you have 300 gallons of water, you can accommodate about 100 pounds of tilapia. Through an increased amount of filtration, you can reduce the tilapia to water tank ratio to at least two gallons of water per pound of tilapia.
What Elements Influence Stock Density?
To provide an ideal environment for your fish, including tilapia, you must satisfy water quality standards. Your system should be able to manage waste based on your fish’s ability to produce it. There may be accepted stocking density, but different factors are at play, including the following:
Sufficient dissolved oxygen makes for excellent water quality. To consistently check dissolved oxygen levels, you will need a dissolved oxygen meter. The pH level also determines water quality. It becomes under 7.0 as the size of fish increases. Additionally, bacteria do not reproduce as ammonia levels rise. However, water exchanges can instantly solve this. Adding more Potassium Hydroxide (KOH) can also regulate ammonia at harmless levels.
In aquaponics, plants serve as a biofilter for recycling waste. To secure good water quality for your fish, you must secure a system with similar production and absorption rate for nutrients. You can maintain warm fish water, get rid of fish solids, and provide pure oxygen water to enhance the growth of your fish.
Size and Type of Fish
Given that tilapia are hardy, they can grow at higher densities. Other fish are too territorial, but considering bioload, they can still work well in your tank. However, you may find it hard to provide sufficient space for them to be adequately far from each other. Superior water quality is also a must for some fish, like trout.
There are fish that need to stay alone, or else they would end up fighting. An example of this includes betta fish. Thus, only combine fish with the same water quality needs.
How To Raise Stocking Density for Your Tilapia
Some aquaponics systems can accommodate more fish for every gallon of water. However, it’s best to go back to the basics, especially if you’re new to aquaponics. Here are some ways you can enhance stocking density for your fish.
Enhance Dissolved Oxygen
As your tilapia grow and more feed is needed, dissolved oxygen in water also declines, impacting nitrification. When evaluating dissolved oxygen, consider the water’s temperature because the dissolved oxygen is also its outcome. You may need to add more aerators in grow beds to increase dissolved oxygen levels, which can help facilitate the nitrification of ammonia. Check the water quality regularly, and modify the amount of food and the pH as needed.
Use an Automatic Feeder
Automated fish feeding is helpful especially when you’re not around to do the feeding. As they work on timers, your fish can still get the same quantity of food. You can also modify the amount of food dispensed. Given that feed needs increase as your fish grows, it’s wise to use an automatic fish feeder.
You can also enhance stocking density by reducing your fish’s food. Doing so can hamper their growth, which is suitable once they become fully grown. However, there should be enough balance between the food taken in and the biofilters’ size. Thus, you need to set up an effective design for your system.
Understand the Tilapia to Water Tank Ratio for Maximum Fish Growth
For every pound of tilapia, you need three gallons of water. While this is the widely accepted ratio, you have to maintain good water quality to facilitate maximum growth for your fish. Several factors affect the stock density, so make the necessary adjustments as the fish grow. Check out our page for more aquaponics tips.