There are two kinds of fish that can be kept in an aquaponics system: ornamental fish and edible fish.
Depending on the size of the tank you have at home and the amount of time you want to dedicate to taking care of your fish, you will have to select which fish to stock and how many.
We’ll give you a rundown first of the most popular fish used for aquaponics, and then provide general recommendations for taking care of your fish and your aquaponics setup.
Tilapia is probably the most popular aquaponics fish around because of its hardiness, ease of maintenance and general availability.
This fish thrives in water with a temperature of 72 to 86 degrees Fahrenheit.
Tilapia reaches harvestable maturity in six to nine months. Male tilapia are larger and provide more meat, so you may want to think about this when choosing the sex of your fish.
Tilapia originates from warmer waters and its meat is versatile and can be cooked into almost any dish. The tender, white meat has a mild flavor that can be seasoned to perfection.
A crowd favorite in many countries, tilapia is a sound choice if you want to either consume or market a mild-tasting fish that grows fairly quickly.
Tilapia are omnivorous, too, which means they won’t pose a threat to other smaller fish in the tank.
Another great benefit of tilapia is their high adaptability levels; even if your tank becomes less than ideal due to unforeseen circumstances, your tilapia will not die off easily.
Hardy and fast-growing, this ancient species that traces its origins to the Nile River in Egypt is considered an ideal fish species for beginners, too.
Are there any downsides to raising tilapia? Power costs-wise, yes.
If you live in a temperate country such as the United States, in a state that is relatively cool most of the year, you will have to warm the water to the ideal range.
If your water reaches 55 degrees Fahrenheit, expect your tilapia to find the environment harsh and challenging, since this species is a tropical species.
A crowd favorite in North America and other countries with temperate climes, trout is the fish that you’d want to raise if you live in a cool state or if your aquaponics setup is in the garage or in the basement.
Trout can survive in water temperatures ranging from 50 to 60 degrees Fahrenheit.
If this is the usual water temperature at home, then you can definitely raise trout.
May aquaponics growers also switch to raising trout during the winter months when they wheel in their system indoors.
Yes, you can definitely design your aquaponics system in such a way that you can shift to an indoor system when the cooler months roll in.
Unlike the tilapia, however, the trout grows much more slowly. In fact, you will need to wait a full sixteen months to be able to harvest a fully mature trout.
But don’t let this stop you: trout is a great source of protein, weighs substantially if you take good care of it, and is a high-demand fish. If you’re planning to sell your fish, there will be demand for it, for sure.
Are there any downsides to raising trout? We’re not sure if you find this a downside (or maybe it is) but trout requires ideal water conditions in order to thrive.
By ‘thrive’ we mean grow normally and ‘on schedule-‘ so that by the sixteenth month you will have trout that has good weight and length, since you already spent so much time rearing it.
Pristine water is clear, has good pH levels and is not inundated with chemicals.
You will also have to make sure that the oxygenation level of the water is high, so that the available oxygen for the fish is consistent throughout the day.
Better aeration can be achieved by using larger air pumps or multiple medium-sized air pumps. In any case, air pumps use little power so using additional pumps shouldn’t incur a huge loss (power cost-wise) to you.
Perch is similar to tilapia with regards to its growing rate. It is ready for harvesting in the ninth month, though its full maturity is attained on the sixteenth month, much like the trout.
The main difference between the perch and the trout is that it is more versatile – it can survive in water that is less than 70 degrees Fahrenheit, though its ideal range is between 70 and 82 degrees Fahrenheit.
Generally speaking, warmer waters can help speed up fish used to warmer waters. In the event that water temperature drops to the mid-fifties, your perch will still survive.
In terms of commercial viability, perch is just as popular as tilapia and is also a versatile, mild-flavored fish with lots of meat and can be cooked in a variety of ways.
It is considered a ‘welcome fish’ for beginners of aquaponics, because it can withstand less than ideal tank conditions.
Take note however that perch are carnivorous fish and live off staples such as shrimp.
Together with the maturity time of sixteen months and you get a good picture as to how long you will be raising this fish from fingerling to plate.
On the bright side, the meat of perch is quite flavorful, so if you’re not too keen on harvesting immediately and you are more concerned with your crops, then you’re off to a good start with this species.
Catfish are tasty, freshwater fish that are best known for converting food to weight fairly quickly.
What this means is that as long as you keep up the regular feeding, your catfish will grow well in the tank. Harvest time from fingerling to plate is between five to ten months.
Like the trout, the catfish is sensitive to sudden changes in water temperature, water quality and pH levels. Regular monitoring of the water is necessary to keep your catfish healthy. There is a market demand for catfish (especially for folks who love Asian cuisine), so there would be no trouble selling the contents of your tank when it is time to harvest your fish.
Catfish are bottom-feeding fish, but they also eat other small fish so keep this in mind if you are keeping fingerlings in the same tank as adult catfish.
Generally speaking, it is a good idea to keep fingerlings away from other adult fish during the vulnerable stage if you do not want to lose a handful (or all) of them.
You can feed your catfish regular fish fare like pellets, or plant matter. The tilapia’s diet can also be the catfish’s diet.
The barramundi is a warm-water, fish that grows to full plate size in about a year from fingerling stage.
This species is popular not just in aquaponics systems but also in general aquaculture, because of its flavorful meat and high market demand. The barramundi is sought after particularly in Australia.
What is interesting with the barramundi is that it can be kept in both saltwater and freshwater tanks.
The downside to it however, is it has been known to harass and attack smaller fish in the tank.
This aggressiveness is attributed to its territoriality, so expect aggressive behavior especially when you have a tank full of male barramundi.
To be fair to the barramundi species, territorial behavior is observed in all fish species, not just in the barramundi.
This species thrives in water with a temperature of 78 to 83 degrees Fahrenheit and has flaky meat that is tasty in every preparation.
The high rate of growth means this fish eats frequently and metabolizes food quickly, too. High metabolism means more fish waste in general, so your growing crops will have a steady stream of nutrients, definitely.
Who doesn’t love bass? Bass is probably one of the first fish you’ve caught while you were learning how to cast and now, it’s headed straight for your aquaponics system!
The bass requires a water temperature between 75 to 85 degrees Fahrenheit and reaches full maturity in 18 months.
The minimum harvesting time for bass is 12 months, though the larger and meatier bass are ready in 18 months.
All variants of the bass, including the large-mouth bass and striped bass are all alright for aquaponics setups.
The downside, once again, is that this species is less hardy than tilapia, and doesn’t show the same adaptability as this previous species. So if you are a beginner, you may want to try out other species before experimenting with bass.
If you want bass that grows more quickly and is ready for plate in a shorter period of time, we recommend the striped bass variant.
But if you really want to raise bass, you need to be up for the daily monitoring of the fish tank’s water condition to make sure that the pH level is just right and there are not issues.
Shock can occur when bass is left to fend for itself without human intervention in an enclosed system.