With over 30,000 species of fish, it can be daunting knowing which direction to go while setting up your aquaponics system and choosing your stock fish. Each type of fish has its own specific needs, and it’s important to understand what you’re getting yourself into when you start stocking your tank. Just like the varying aquaponics system types, some species will be better suited to your needs than others. Once you’re settled on a garden design and have a good idea of how you want the final setup to run, you’re ready to choose your fish.
The 11 Best Fish for Aquaponics
Tilapia come in several varieties, and while they do best in warm water, tilapia can adapt to some cooler temperatures. The most appealing aspects of tilapia are that they are hardy, breed easily, and people enjoy their harvest. Tilapia is at the top of the list, because they are the most popular aquaponics fish to stock. Because of this, tilapia might be a good choice for a beginner, as there are plenty of resources about growing tilapia in an aquaponics setting to help you on your way. That being said, tilapia are not legal to own in all U.S. states, so check with your local Department of Natural Resources (DNR) to see if this is an option for you.
When people farm trout in aquaponics systems, they are usually talking rainbow trout. These fish need cool waters, so you’ll have to be sure you’re in a position to keep the water around 60°F. Trout are a favorite for the dinner plate, but they do require a bit more complex care than others. For cool climate aquaponics systems, the investment into proper trout care may be worth it considering that the trout will thrive in the cool environment where many other popular fish will struggle. These fish grow quickly, but they will not breed in aquaponics systems. This means you’ll have to purchase new trout whenever your stock runs low.
Catfish are another family favorite, and they make a great substitute for people who can’t farm tilapia. They require nearly identical setups as tilapia, so you can even farm them side by side.
Catfish are a more sensitive fish, however, so you need to be prepared to monitor water quality and temperature closely, or you risk losing your stock.
Koi are generally an ornamental aquaponics fish and can grow to be several feet long depending on the type. While you can harvest them for food, most people keep koi without that intention. You can keep them as tank partners for harvestable fish, though. For someone not interested in fish harvest and investing in a larger setup, koi may be a great choice. While rather expensive to first purchase, they are very hardy fish and live for upwards of four decades, so as long as you keep up with their care, you won’t need to restock your tank for a long time with koi.
There are a couple types of perch you can use in aquaponics, including the jade perch and the silver perch. While the perch, like trout, won’t breed in your aquaponics system, they are still a very popular choice thanks to their hardiness and taste. They grow a little more slowly than others, meaning you won’t begin harvesting until a year in or more, and they do require warm water and some extra care to provide proper water aeration. They need a carnivorous diet, which tends to be more expensive, but many people consider it well worth the cost considering the return you will get on your plate.
There are a few different types of bass to choose from, but they are all fish that can do well in cool environments and are readily accessible. Bass are sensitive to water quality, so someone choosing this fish will have to be prepared to monitor their system closely and know how to take action to remediate the tanks when necessary. Some types of bass are slow-growers, but they remain a solid choice for someone with experience, patience, and an appreciation for a rewarding harvest.
 Murray Cod
One of the biggest pros for growing Murray cod in your aquaponics system is their high stocking density. Someone looking to harvest more often might opt for this type of fish, although it does take at least a year before they will be at the right size. They make great tank mates for perch, but you must be cautious of keeping them with small fish once they are adults, because they will tend to eat whatever they can fit in their mouths. Cod can live for decades, so they could also work well for someone looking to have a long-lasting garden where restocking does not have to happen very often. Keep in mind that cod are very large fish, so these will only work for large-scale operations.
Goldfish are a great non-harvestable option for beginner aquaponics gardeners. They can live for over a decade, and are very hardy in terms of wandering water pH. For most people, they won’t require extra aeration, heaters, or other special equipment. These fish are very accessible, inexpensive, and are a great learner fish. Goldfish do grow to be big for aquarium fish, despite misconceptions, averaging to a little less foot in length in adulthood when provided proper care, so plan accordingly.
[9 & 10] Guppies and Tetras
Guppies and tetras can be paired together in tanks, and are the perfect choice for people with aquaponics mini-gardens. Their small size and water quality tolerance makes them suitable to smaller tanks that none of the other fish on this list would be able to live in.
If you’re an apartment aquaponics gardener with strict size limitations, guppies and tetras might be your best bet.
OK – crustaceans aren’t technically fish, but they can act as tank mates for a variety of fish and be an exciting addition to an aquaponics system. They clean up on the bottom of the tank, and the majority of those kept in aquaponics systems are harvestable. Some, like lobsters, can be very slow-growing, but others can be ready in as little as six months. There are lots of different species of crustaceans available for aquaponics, so if you’re considering pairing them with your fish, ask your supplier which variety will work best with your setup.
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Factors for Choosing Your Aquaponic Fish
Sit down with your design and think about what these details look like for you before choosing the fish for your garden.
Your local climate and whether the garden will be inside or outside will determine the temperature of your tanks and how much the temperature will change between night and day. Unless you’re willing to foot a hefty electric bill, choosing warm water fish for a garden set up in an area that routinely experiences cold weather might not be the best choice. Similarly, if you are stocking an outdoor aquaponics garden in an area that has extreme night to day temperature fluctuations, you’ll probably want to choose fish that can tolerate those changing conditions.
Size of Fish
Fish don’t stay hatchlings forever. Make sure that the fish species you choose does not grow too big for your tank size. Large scale aquaponics farms have the option for large fish that a tiny setup in the corner of an apartment does not. Be sure to account for the adult size of the fish when purchasing the amount and type to stock your tank.
Some people like to produce their own stock rather than order new after the first initial garden setup. Consider if this is a route you would like to take, and if it is, choose a fish species that will be able to breed in your aquaponics tanks and one that will be within your means to breed. Learn about breeding habits and necessities to make sure that you will be prepared to handle the breeding process when the time comes.
If you aren’t going to harvest your fish, on the other hand, a fish species that will not readily breed on its own in the tanks is a good choice. If you choose a species that breeds quickly and you aren’t harvesting from the stock, your tanks could become overstocked, causing imbalances in the chemical processes that produce fertilizer for the plants. The plants may not be able to keep up with removing the waste the fish produce, and this would result in dirty water going back into the fish tank. In addition to the threats from these imbalances, overcrowding can cause disease and stress, which could eventually kill your fish stock altogether.
Make sure the fish species you choose is within your budget to keep up with stock needs. This is especially true if you will be needing to make additional purchases of fish after the initial stocking. The factors influencing price include species and whether you intend to buy juvenile fish or fully-grown.
After you choose a species that works well with your environment and individual expectations of the garden, make sure you consider the stocking density before purchasing your first fish. Some fish require more space than others, and if you accidentally purchase too many, you risk exposing your fish to dangerous overcrowding conditions as discussed above.
Consider whether you intend to harvest the fish or treat them more as pets. Some aquaponics fish species are non-harvestable, but make for fun pets and are easier to care for than some of the harvestable fish. If you do want to harvest the fish, decide how often you want to be able to harvest, and make sure you choose a species that will grow fast enough, breed fast enough (if you intend to replenish your own stock), and can live well at a stocking density that will support your needs.
This one is easy enough. Choose a fish species that is within your means to care for. This goes for your skill level, financial capabilities, and space limitations. Some fish will require heaters, extra water aeration, or special food, so make sure you know that ahead of time. You want to be sure that you’re prepared for the investment beyond the purchase of the fish themselves.
Some aquaponics gardens hold more than one species of fish. If this is something you’re interested in pursuing, read up about whether the species you want to cohabitate are compatible. Check that the species do well in the same temperature, pH range, stocking densities, and other care factors, and make sure that they have personalities that support living with species that are not their own. Also consider the size difference between the species you’re looking at purchasing. Cohabitating large predatory fish with small ones, for example, will likely only end with your large fish harvesting your small fish for you.
When you’re ready to purchase your aquaponics fish, you can often find the non-harvestable options at your local pet store. Others will likely have to be purchased through a commercial supplier. Some people may be able to find local suppliers for pickup, otherwise your fish will have to be bought online or over the phone and shipped to your address. Suppliers are great places to take any specific questions about your fish, and they are great people to guide you further in making an informed decision about the best fish for your garden.