Aquaponics combines conventional aquaculture with hydroponics to form a highly sustainable and environmentally responsible method of Agriculture.
Aquaponics systems come with many benefits – very low water consumption as compared to traditional agricultural means, low energy usage, little to no chemical usage, and low susceptibility to pests and diseases.
Fish play a key role in an aquaponic system as they provide the by product which converts into a consumable plant food.
But each species of fish has its own environmental requirements for successful habitation. This article will break down the differences between 9 of the best types of fish for your system.
In this article, we'll cover:
- The best fish for aquaponics: species, and pros and cons
- How and where to purchase fish online and what precautions to take when ordering
- What factors to consider when selecting fish for your aquaponic system
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What Are the Best Species of Fish to Use for My Aquaponics System?
- Temp: 82 - 86°F / 28 - 30°C
- pH level 6.5 - 9.0
- Breed every 4-6 weeks
- Great for beginners
Tilapia originated in the wild in Africa and in the Nile River Basin of Lower Egypt and is considered to be one of the oldest farmed fish on the planet.
Their high protein content, omnivorous diet, large size, and rapid growth, have made them popular among aquaponics users. They prefer water with a pH level between 6.5 - 9.0.
Tilapia are quite resistant to parasites and diseases making them an excellent choice for beginners. They thrive in water temperatures between 82-86 degrees F but are usually kept in lower temperatures to accommodate the plants. They're easy to breed and grow quite quickly – up to 2.5 lbs. in 7 months.
One thing to consider is that Tilapia can breed almost too efficiently – spawning every 4-6 weeks so a second tank might be helpful in containing the babies.
Tilapia can be quite costly to maintain as farmers need an energy source to maintain a tropical temperature range in their tanks as they require warm water.
- Temp: 66 - 70° F / 18 - 21° C
- pH level 6.5 to 8.5
- Breeds once a year
Perch is a great choice for aquaponics because of its taste, hardiness, growth rate, and nutrition. Perch are better at retaining omega 3's than any other fish when fed with feeds high in omega-3 oils. Perch will not breed in captivity, but they have a fast growth rate.
There are three main perch species: the European Perch – found in Europe and Asia, the Balkhash perch – found in Kazakhstan, Uzbekistan, and China, and the yellow perch – found in the US and Canada.
The yellow perch, in particular, are best for aquaponics due to their moderate temperature range and wide pH range. Thriving in temperatures between 66 and 70 degrees F, these carnivorous fish typically reach about 15 inches in size and 2.2 lbs. in weight.
With a pH range of 6.5 and 8.5, they have the widest among the aquaponic fish species. Perch only breed once a year and require a sudden change in temperature from cold to warm – as to simulate the change from winter to spring.
- Temp: 45 - 75° F / 7 - 18° C
- pH level 6.5 to 8.0
- Requires large tank for optimum growth
- Requires oxygen level of at least 5.5mg/L
Trout are closely related to salmon and char and are one of the most widely farmed fish in the world. Most trout live in freshwater lakes and rivers, spending two or three years at sea before returning to freshwater to spawn.
They generally feed on other fish and soft-bodied aquatic invertebrates such as flies and dragonflies. They may also feed on shrimp and small animal parts. Unlike tilapia, trout will not handle dirty water.
Trout are somewhat bony, but the flesh is generally considered to be tasty. The flavor of the flesh is heavily influenced by the diet of the fish.
Among the three most common types of trout – brown, rainbow, and brook – rainbow trout make the best species for aquaponics due to their hardiness.
Rainbow trout can withstand the varying conditions an aquaponics system will present.
They are considered cold-water fish and thrive in temperatures between 45 and 65 degrees F. They require a pH range between 6.5 and 8.0.
Trout can grow to about 15 inches in 9 months but require a large lank for them to grow in. Also, they require an oxygen saturation of at least 5.5mg/L. Stocking density is something to pay close attention to so as to make sure that there's adequate oxygen for all the fish.
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- Temp: 65 - 80° F / 18 - 26° C
- pH level 6.5 to 8.5
- Can grow up to 12 lbs.
- Requires large tank for optimum growth
- Keep away from bright light
Bass, a popular American game fish, are very hardy and can tolerate low water temperatures. Bass eat worms, insects, larvae as well as high protein pellets. They prefer to feed on food that stays on the surface or that sinks slowly, rather than to feed off the bottom of the tank.
There are many species of Bass to choose from. These are among the most popular for aquaponics:
- Hybrid striped bass is well suited for aquaponics as they are hardy and resilient to extremes of temperatures and low dissolved oxygen.
- Smallmouth bass is carnivorous and eats crayfish, insects, and smaller fish. They can tolerate cool water but are reluctant to eat pelleted food
- Largemouth bass – The northern strain and the Florida strain is generally larger and live much longer.
- Australian bass is small to medium-sized. They feed on insects, or on protein-rich pellets.
Though not considered a beginner species for aquaponics, Largemouth bass is widely used in aquaponics systems due to its potential for growth. A full-sized adult largemouth bass can reach 12 lbs. in weight in 16 months.
Largemouth bass do not like bright light. They require a strict feeding regime of small shrimp and insects as a baby and then snails and crayfish as an adult. They require a steady water temperature between 65 to 80 degrees and prefer a pH level of 6.5 to 8.5.
Though much maintenance is required for largemouth bass, their size and hearty meat provide a very rewarding harvest.
- Temp: 75 - 86°F / 24 - 30° C
- pH level 7.0 to 8.5
- Can tolerate wide range of water conditions
- Good choice for beginners
Catfish are one of the most farmed types of fish and are sought after for their taste - their meat is consumed as a delicacy around the world. Catfish are omnivorous bottom feeders and valuable scavengers.
They are strong and can withstand a wide range of water conditions. They are not territorial and can tolerate a higher stocking density. Catfish are easy to breed and grow, and within 3 months can be harvested for cooking.
Catfish thrive in a similar temperature range as tilapia at 75 to 85 degrees F and have a pH range of 7 to 8. They grow fast and can reach 2-3 lbs. in 12 months.
- Temp: 71 - 80° F / 22 - 27° C
- pH level 7.2 to 8.0
- Special care needed for fingerlings
- Grows extremely fast
- Delicious and extremely nutritious
Barramundi is an excellent table fish highly regarded in most restaurants and a great fish for Aquaponics, but not recommended for beginners. They prefer warm water are reputed to be fast growers.
However, they are hard to grow as Barramundi fingerlings need to be graded to survive. The fingerlings attack and eat one another – the larger-sized fish will nip and wound the smaller fish. The wounded smaller fish will eventually die if not eaten by the others.
Barramundi need lots of dissolved oxygen going into their tank and they need very good quality water.
Barramundi thrives at a specific range of 71 to 80 degrees F and a pH range of 7.2 to 8.0.
Despite the specific conditions and amount of care necessary for successful farming, Barramundi has one of the fastest growth rates among fish in an aquaponic system and is harvestable at 1 lb. in a 6 month period. They have a highly prized meat that is extremely nutritious and high in Omega fatty acids.
- Temp: 68 - 77° F 20 - 25° C
- pH level 7.5 to 8.0
- Resilient in different water conditions
Carp is a species of oily freshwater fish, native to Asia. Various species of carp can be reared as food. They are omnivorous and can feed on algae, plants, insects, and many other soft-bodied aquatic invertebrates. Carp have good reproductive capabilities and can easily adapt to various environments.
Over the past few years, the demand for carp in Western Europe has declined as more desirable table fishes, trout and salmon, have become more available through extensive farming. Nevertheless, Carp make a good species for aquaponics due to their resilience to changes in water conditions.
They have a temperature range of 68 to 77 degrees F and a pH range of 7.5 to 8.0.
- Temp: 59 - 77° F / 15 - 25° C
- pH levels 7.0 to 8.0
- Great for beginners
- Highly successful in aquaponics due to hardiness
- Resistant to most disease and parasites
Koi is one of the most popular fish used in aquaponics. They have a long lifespan and can easily live and breed within the aquaponic system. Koi are also fairly disease and parasite-resistant. They are omnivores and can eat just about any food.
As they eat algae, debris, and plant matter that fall into their pond, additional feeding may not be necessary. Waste production will have to be monitored and a large and more efficient filter may need to be installed.
Koi are not considered to be a good fish for eating, so you will have to seek alternatives. They thrive in temperatures of 59 to 77 degrees F and pH levels of 7.0 to 8.0.
They are highly successful among beginners due to their adaptability and resilience.
- Temp: 78 to 82° F / 25 - 27° C
- pH levels 6.0 to 8.0
Goldfish are an ideal aquaponics fish as they produce and eat a large amount of excretion, thus providing plenty of nitrates for the plants.
They are also hardy, depending on which species you select. However, rapid changes in temperature can be fatal.
There are generally two types of goldfish – twin-tailed and single-tailed. Be mindful to avoid mixing these two species together as twin-tailed fish could end up suffering greatly. As single-tailed goldfish have slim bodies and are more aggressive and faster swimmers, twin-tailed gold finds it hard to compete with them.
Goldfish are inedible ornamental fish and thrive in temperatures of 78 to 82 degrees F and pH levels of 6.0 to 8.0.
How and Where to Purchase Fish Online
Online transactions have revolutionized how we purchase items and live fish are no exception. Yes, it is possible to have live fish shipped to your door by a reputable company via expedited shipping and proper packaging. Here are some tips for ensuring you have a hassle-free buying experience.
- Select a Reputable Vendor - Be sure to read the reviews posted by other customers and ensure that the vendor is reliable in their packaging and delivery of the live fish. Make sure the fish they are selling are healthy and well.
- Look for Guarantee - Only purchase from stores that offer a guarantee that their fish will arrive alive and will offer a refund for any other outcome.
- Expedited Shipping Only - Most reputable online fish vendors will only sell ship the fish under expedited or next-day service due to the time-sensitive packaging, but it doesn't hurt to double-check for it.
- Be Home When it Arrives - Expedited shipping is great in ensuring that it arrives at your doorstep on time but it doesn't help if the package is sitting on your front porch while you're on vacation. Be sure that someone is home to place the fish in their proper conditions right away to ensure optimum health.
Reputable Online Stores
What to Consider When Choosing Fish Species for Your Aquaponic System
Ornamental vs Edible Fish
Fish edibility plays a major factor in your species selection. If you intend to eat your fish, construct your system around edible fish species.
Otherwise, some of the inedible fishes – Koi and Goldfish – do have the benefit of being much easier to maintain.
Goldfish, while slightly more difficult to maintain than Koi, are much less expensive and can be used for smaller aquaponics systems or trial runs.
Koi fish are great for beginner systems as they're quite resilient to the volatility a new aquaponics system can present. They're also very resistant to diseases and parasites, two things that can turn a well-maintained aquaponic system upside-down.
Edible fishes have the benefit of being eaten but often require much more specified conditioons.
Breeding, growth rate, and stocking density
Breeding is a factor to consider when purchasing fish and when considering the type of system set-up as a whole. Some species don’t reproduce easily in a controlled tank which can be frustrating, especially for beginners.
Others, such as Tilapia and Catfish breed quite quickly, which can also lead to complications if the system isn't built properly for it.
Spawning vs Livebearing - There are two main methods fish used for breeding – spawning, and live-bearing. Most fish spawn, whereas a fair number of fish are livebearers.
Spawning involves reproducing freely by laying eggs when special conditions, known as spawning triggers, are met. Live-bearing involves retaining eggs inside the body and live birth to free-swimming young.
Livebearers are generally preferred for fish-breeding. Live-bearing aquarium fish, often simply called livebearers, are fish that retain the eggs inside the body and give birth to live, free-swimming young.
Growth Rate - The growth rates of fish vary. With your aquaponic system, it is better to have fish with a range of growth rates to harvest fish regularly over a long period of time.
The range of fish growth rates varies. It is also important to consider the time of year at which the fish are ready to be harvested. Overcrowding is an issue that needs to be addressed as we'll see in the next section.
Population Density - You will have to stock your tank with a reasonable number of fish, keeping in mind the growth rate of the fish, the available space in the tank, and your budget for purchase and maintenance. The size your fish could grow up to should also be kept in mind when considering the available space.
An overcrowded fish tank can disrupt the oxygen and ammonia levels in the water, as can an underpopulated tank. Keep population density in mind when harvesting fish as well.
In terms of diet, fish can be classified into three main categories – herbivore, carnivore, or omnivore. Fish suitable for aquaponics systems are either carnivore or omnivore.
Carnivores require a high protein diet which can be difficult to achieve without purchasing high-quality commercial feed specifically formulated for carnivorous fish. Some carnivorous fish may prefer to feed on other fishes instead, especially the young and weak.
So generally, carnivores cannot be mixed with other species and they should all be of approximately the same sizes to prevent them from snacking on each other.
Omnivores can coexist with their own species and with other omnivorous fish species, so they are an excellent choice for a community tank. Omnivores are also known to be the easiest to feed.
You will need to maintain your aquaponic system by testing the water, changing the water, and checking your equipment, but your fish will also need some maintenance.
Some fish are difficult to care for whereas others are relatively easier. Your fish may fall ill or experience bullying, resulting in you having to administer medication to your fish or put your fish in isolation.
Fish are cold-blooded animals – they take on the temperature of the water in which they live, so temperature plays a very important role. The water temperature requirements of fish depend on their natural climate.
For example, fish originating in the lake waters of Africa such as tilapia have evolved to thrive in warm water (above 70oF), whereas fish originating in streams of North America such as trout have evolved to thrive in cold water (55oF and below). So, when choosing your fish, you should be mindful about what water temperature you will be able to provide.
The fish and plants you select for your aquaponic system should also have similar needs in terms of temperature. The closer they match, the higher the chances of success of your aquaponic system.
The pH control of your aquaponic system is essential for the health of your fish. An inappropriate pH level can cause poor fish growth and may lead to the death of your fish. So, you need to know what results in high pH or low pH levels in your aquaponic system, and how you can balance the levels within the appropriate range.
It is important to match the pH of water in the fish tank with the water in the fish bag when you are introducing new fish into your system. The difference between the pH values should not be greater than 0.2. As with temperature, the fish and plants you select for your aquaponic system should have similar needs in terms of PH Sensitivity. This improves your chances of success as well. Read our related article on how to balance pH in an aquaponic system.
Video: Choosing the Best Fish for Aquaponics
Watch this video discussing the process in choosing the best fish for your aquaponics system.
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