The Best Fish for Desktop Aquaponics Systems

In aquaponics, fish produce nutrient-rich waste that, when processed by beneficial bacteria, becomes natural fertilizer for plants. The plants, in turn, help filter and clean the water, creating a balanced, self-sustaining ecosystem. The beauty of aquaponics lies in this cycle: it’s low-maintenance, conserves water, and brings together the best of both gardening and fishkeeping.

Small-scale or desktop aquaponics systems take this concept to a new level of accessibility, making it possible to enjoy the benefits of aquaponics in homes, apartments, or even office spaces. Desktop aquaponics setups are not only visually appealing, but they also purify the air, foster a connection to nature, and offer a unique way to grow herbs or small greens right at your desk. They’re a practical option for anyone looking to experience sustainable gardening on a small scale without the need for an outdoor garden.

However, for a desktop system to thrive, it’s essential to choose fish that can adapt well to smaller environments and are compatible with plant growth. This article is here to help guide you through selecting the best fish for your desktop aquaponics system. We'll cover hardy, low-maintenance fish species that can thrive in indoor conditions, providing a foundation for a healthy, balanced ecosystem.

What is Desktop Aquaponics?

Aquaponics is a method of cultivation that merges aquaculture, the practice of raising fish, with hydroponics, a soilless method of growing plants. In an aquaponics system, fish waste supplies natural fertilizer for plants, while the plants filter and clean the water, creating a symbiotic relationship that supports both fish and plant life in a self-sustaining cycle. The process is powered by beneficial bacteria that break down fish waste, converting it into nitrates and other nutrients that plants can absorb, which in turn keeps the water clear and safe for the fish.

Desktop aquaponics takes this eco-friendly concept and scales it down to a miniature version that fits on a desk or countertop. In these smaller systems, fish like bettas, guppies, or other small, hardy species coexist with compact plants such as herbs, lettuce, and microgreens. These systems are designed to be compact, simple, and easy to maintain, making them ideal for those with limited space or beginner-level gardening experience. Whether in a home office, kitchen, or bedroom, desktop aquaponics systems bring a slice of nature indoors, requiring only a small amount of water and space while adding a fresh, green touch to any area.

Desktop aquaponics setups offer several unique benefits:

1. Space Efficiency: Unlike traditional aquaponics setups, desktop systems require minimal room, making them suitable for small apartments, desks, or office spaces.

2.  Air Purification: As the plants in the system photosynthesize, they help improve indoor air quality, creating a healthier and more pleasant environment. Indoor plants have been shown to reduce pollutants, creating a natural air filter that can make any room feel fresher and more vibrant.

3.  Sustainability: Desktop aquaponics systems are environmentally friendly, conserving water through recirculation, and creating a closed-loop system that requires fewer resources than traditional gardening.

4.  Aesthetic Appeal: Desktop aquaponics systems have a unique aesthetic that combines the calming presence of fish with the vibrant greenery of plants. They add life and beauty to a room and create a tranquil, nature-inspired focal point that can boost mood and reduce stress.

Factors to Consider When Choosing Fish for Desktop Aquaponics

Fish that are well-suited for small, indoor setups will help keep the system manageable and promote healthy plant growth. Here are the key factors to consider when selecting fish for your desktop aquaponics system:

1. System Size:

Desktop aquaponics systems typically use small tanks, often holding between 1 and 5 gallons of water. Because of limited space, the fish you choose should be comfortable in a small environment and require minimal swimming room. Fish that thrive in close quarters, such as bettas or guppies, are ideal choices. Avoid fish that grow quickly or need large amounts of swimming space, as they can become stressed in smaller tanks. 

2. Fish Hardiness:

In small aquaponics systems, water parameters like pH, ammonia, and nitrate levels can fluctuate more readily, which can stress sensitive fish. To avoid this, select fish that are known for their hardiness and ability to tolerate minor changes in water quality. Hardy fish species can adapt to less-than-perfect conditions, which makes them more suitable for smaller, closed-loop systems. 

3. Water Temperature & pH Requirements:

Desktop aquaponics systems are usually kept indoors at room temperature, so it’s best to select fish that are comfortable in this range, generally between 68°F and 78°F (20°C - 25.5°C). Choosing fish that align with room temperature eliminates the need for a heater, simplifying the setup and reducing maintenance. Similarly, selecting fish that thrive in a neutral pH (around 7) helps maintain compatibility with a variety of plants.

4. Compatibility with Plants:

The waste produced by fish serves as natural fertilizer for plants, but the type and amount of waste each species produces vary. Smaller fish typically generate a manageable amount of waste, which is ideal for small plants like basil, lettuce, or mint. Certain fish produce more solid waste, which can benefit leafy greens but may not be ideal for more delicate plants.

5. Noise and Odor:

Since desktop aquaponics systems are often placed in work or relaxation areas, it’s essential to choose fish that are quiet and low-maintenance. Some fish are more active and can create noise by splashing or agitating the water, which might be distracting in quiet spaces.

Top Fish for Desktop Aquaponics Systems

Here are some of the best fish options, each with unique pros and cons and ideal plant pairings to create a thriving mini-ecosystem.

1. Betta Fish

• Pros: Bettas are well-suited to small, low-maintenance systems, known for their hardiness and resilience. They have a relatively low waste output compared to other fish, making them ideal for small tanks. Bettas are also highly adaptable, requiring minimal equipment, which keeps maintenance simple.
• Cons: Bettas are tropical fish, so they prefer water temperatures of around 75-80°F (24-27°C), which might require a small heater. They are also solitary and territorial, meaning they are best kept alone or with certain compatible species in desktop aquaponics setups.
• Best Plants: Bettas do well with herbs like basil and mint and small greens, as these plants thrive in the nutrient-rich waste produced by bettas while helping to filter the water for a balanced ecosystem.

2. Guppies

• Pros: Guppies are colorful, lively, and small, making them an excellent choice for desktop systems. They are easy to care for, require minimal equipment, and thrive in small groups, adding life and activity to the setup. They are also relatively hardy and can adapt to a range of water conditions, provided they have clean, stable water.
• Cons: Guppies breed prolifically, which can quickly lead to overpopulation if not managed. A separate breeding tank or a plan for population control may be necessary.
• Best Plants: Guppies work well with fast-growing, leafy greens such as lettuce or kale. These plants absorb nutrients effectively, making them well-suited to handle the nutrient input from a small group of guppies.

3. White Cloud Minnows

• Pros: White cloud minnows are hardy and can tolerate cooler water temperatures, so they don’t typically require a heater, making them a great choice for indoor systems. They are peaceful fish that thrive in small groups, adding a serene visual appeal.
• Cons: White clouds need clean water and are sensitive to high ammonia levels, so regular water monitoring and a good filtration setup are important for their health.
• Best Plants: Spinach and chives are excellent plant choices for white cloud minnows. These hardy plants can handle the nutrient load from the fish without requiring intense sunlight, making them compatible with indoor conditions.

4. Zebra Danios

• Pros: Zebra danios are hardy, adaptable, and tolerate varied water conditions, making them ideal for beginners and small-scale aquaponics. They do well in groups, are relatively small, and can adapt well to different pH levels.
• Cons: Danios are very active swimmers and may prefer slightly more room to move, so a desktop system with a bit more horizontal space can work best for them.
• Best Plants: Fast-growing plants like watercress and mustard greens work well with danios, as these plants quickly absorb the nutrients from fish waste, keeping water quality stable and supporting the health of the ecosystem.

5. Dwarf Crayfish (for variety)

• Pros: Dwarf crayfish offer something different from typical fish. They add a unique element to the aquaponics system with their interesting behavior and scavenging habits, which help keep the tank clean. They also have a low waste output, making them suitable for small aquaponics setups.
• Cons: Dwarf crayfish require hiding spots to feel secure and may occasionally nibble on more delicate plants, so they need hardy plant companions.
• Best Plants: Basil, thyme, and other hardy herbs are ideal for tanks with dwarf crayfish, as these plants can tolerate the occasional nibbling and still thrive in a small, controlled system.

Fish to Avoid in Small Aquaponic Systems

Not all fish are suitable for desktop aquaponics systems. While some species thrive in smaller tanks with minimal maintenance, others require much more space, produce excessive waste, or are too delicate for confined, fluctuating conditions. Here’s a quick overview of fish types best avoided in small aquaponics setups:

1. Goldfish

• Why to Avoid: Although goldfish are popular for home aquariums, they are unsuitable for small aquaponics systems due to their high waste output. Goldfish produce a significant amount of ammonia, which can quickly overwhelm a small tank and harm both plants and fish. Additionally, they grow much larger than most people expect, often requiring much more space and filtration than a desktop system can provide.

2. Large Cichlids

• Why to Avoid: Cichlids, such as oscars and African cichlids, are known for their vibrant colors and engaging personalities. However, these fish grow quite large and can be highly territorial, making them unsuitable for small, shared tanks. They also have a high waste output and require stable water conditions, which are hard to maintain in small desktop systems. Additionally, cichlids may dig in gravel or substrate, disturbing plant roots and creating a messy tank environment.

3. Plecos and Other Bottom-Dwellers

• Why to Avoid: While certain small catfish or shrimp may work well in desktop aquaponics, plecos (especially common and sailfin plecos) are not ideal. These bottom-dwellers grow large over time, produce significant waste, and are very active in searching for food. They require more space than a small tank offers and are best suited to larger aquariums with plenty of hiding spaces and filtration. Additionally, their waste load can quickly compromise water quality in a compact system.

4. Angelfish

• Why to Avoid: Angelfish are beautiful but delicate fish that can be challenging to care for in small, fluctuating environments. They require stable water conditions and a specific pH range, making them better suited for larger, well-maintained aquariums. Their taller body shape also makes them more comfortable in deeper tanks, which desktop systems rarely provide. Moreover, angelfish can become territorial, especially in cramped spaces, which may disrupt a small aquaponics system’s harmony.

5. Large or Specialized Fish

• Why to Avoid: Other large or specialized fish, such as koi, arowanas, and discus, should also be avoided in small aquaponics setups. These species require specific water conditions, larger tanks, and specialized diets, making them incompatible with the limited environment of a desktop system. Their needs far exceed what a small setup can offer, both in terms of space and water stability.

Setting Up and Maintaining Your Fish-Friendly Aquaponics System

Here’s a guide on setting up a healthy environment and essential maintenance practices to keep your desktop aquaponics system running smoothly.

A.  Tips for Creating a Balanced, Healthy Environment for Fish and Plants

1. Tank Size and Placement

• Choose the Right Tank Size: Select a tank size that’s appropriate for the type and number of fish you’re housing. Most desktop aquaponics systems work well with tanks ranging from 1 to 5 gallons, but larger setups are beneficial for more stable water quality.
• Stable Environment: Place your aquaponics system in a location with stable room temperature, indirect sunlight, and minimal vibrations or disturbances. Avoid placing the tank near heating or cooling vents, which can cause temperature fluctuations.

2. Selecting the Right Fish and Plants

• Hardy Fish Species: Choose hardy fish that are suitable for small aquariums and can tolerate minor fluctuations in water quality. Bettas, guppies, and white cloud minnows are popular choices for small aquaponics systems.
• Complementary Plants: Select plants that are well-suited to aquaponic systems, such as herbs (basil, mint) or fast-growing greens (lettuce, spinach). Plants with nutrient-absorbing roots are ideal for filtering fish waste from the water.

3. Adding Beneficial Bacteria

• Establish a Nitrogen Cycle: Beneficial bacteria play a critical role in converting fish waste into plant-available nutrients. Allow the tank to cycle before adding fish by adding fish food or ammonia and waiting for beneficial bacteria to populate. This typically takes a couple of weeks and helps prevent harmful ammonia spikes.
• Bacteria Supplementation: You can also add bacterial supplements specifically designed for aquaponics to speed up the cycling process and establish a healthy nitrogen cycle more quickly.

4. Lighting Considerations

• Provide Sufficient Light for Plants: Position the system near a source of indirect natural light, or add a grow light if necessary. Plants need adequate lighting for photosynthesis, typically 8-12 hours per day. Avoid direct sunlight, which can overheat the tank and promote algae growth.

B.  Maintenance Tips: Water Changes, Feeding Schedules, and Plant Trimming

1. Regular Water Changes

• Small Weekly Water Changes: Change 10-20% of the tank water weekly to help dilute waste and maintain water quality. Use dechlorinated or treated water to avoid harming beneficial bacteria and fish.
• Ammonia and Nitrate Monitoring: Monitor ammonia and nitrate levels regularly with test kits to ensure they’re within safe limits. If levels are too high, a water change can help bring them down quickly.

2. Feeding Schedules for Fish

• Avoid Overfeeding: Feed fish sparingly, only as much as they can consume in about two minutes. Uneaten food can accumulate, break down, and cause water quality issues, so remove any leftovers after feeding.
• Set a Schedule: Fish generally do well with one or two small feedings per day. Consistent feeding provides a steady source of nutrients for the plants through fish waste but avoids excess that might pollute the water.

3. Plant Maintenance and Trimming

• Regular Plant Trimming: Trim plants as they grow to prevent overcrowding and encourage new, healthy growth. Fast-growing plants like herbs and greens may need trimming every couple of weeks.
• Remove Dead Leaves: Dead or decaying leaves can contribute to ammonia buildup, so remove any fallen leaves or dying parts of plants promptly. This helps keep the water clean and reduces the risk of nutrient imbalances.

4. Algae Control

• Manage Light Exposure: Too much light can cause algae blooms, which compete with plants for nutrients. Use indirect light or a timer for grow lights to limit exposure to 8-12 hours a day.
• Clean Tank Walls Regularly: Scrub algae from the tank walls during water changes if it begins to build up. Algae-eating species like snails may also help control algae, but avoid adding too many, as they can increase the waste load.

5. Check Equipment and Water Parameters

• Monitor Water Temperature: Ensure the water remains within the preferred temperature range for your fish, especially if using tropical species. A small heater may be needed for systems kept in cooler areas.
• Aeration and Filtration: Keep an eye on the filtration and aeration systems to ensure they’re working properly. Filters and air stones help keep the water oxygenated and improve overall water quality.

6. Routine System Checks

• Weekly Health Checks: Observe the fish for any signs of stress or illness, such as clamped fins or unusual behavior. Healthy fish contribute to a balanced system, while stressed or sick fish may produce excess waste.
• System Adjustments: Adjust lighting, plant trimming, and water changes based on the system’s needs. Over time, as fish grow or plants mature, small adjustments may be needed to keep everything in balance.

Conclusion

Setting up a desktop aquaponics system is a rewarding way to bring nature into your home or office, combining the beauty of plants with the calming presence of fish. With a little effort in choosing the right species and regular maintenance, you can create a thriving, sustainable ecosystem that purifies your space, grows fresh herbs, and offers a unique, living focal point.

Ready to get started? Explore the fish and plants that best fit your space and preferences, and dive into creating your own desktop aquaponics system.Start small, stay consistent, and watch as your mini-ecosystem flourishes right before your eyes!