Aquaponics in Small Spaces: Create Your Mini Ecosystem

What You’ll Learn About Small-Space Aquaponics

• How to combine fish raising and plant growing in limited spaces
• Various compact system designs perfect for apartments and small homes
• Essential components needed for a successful mini aquaponic setup
• Best fish and plants for space-constrained systems
• Practical maintenance tips to keep your ecosystem thriving

Introduction to Small-Space Aquaponics

Aquaponics brings together fish farming and soil-less plant growing in one connected system. It’s perfect if you live in an apartment, have a small balcony, or just a tiny corner in your home. The fish waste feeds the plants, and the plants clean the water for the fish – it’s like having a tiny ecosystem right in your living space!

Key Takeaways: Small-Space Aquaponics

• Aquaponics uses 90% less water than traditional gardening while creating a self-sustaining ecosystem
• Three main system types work well in limited spaces: countertop micro-systems, vertical wall-mounted designs, and balcony setups
• Small fish like guppies, goldfish, and minnows work best in compact systems (1 inch of fish per 5 gallons for micro-systems)
• Leafy greens and herbs thrive in small aquaponic systems and provide quick, continuous harvests
• A properly cycled system with regular maintenance requires only 5 minutes daily and 15-30 minutes weekly to maintain

The beauty of small-scale aquaponics is that it uses up to 90% less water than regular gardening. You get to grow food in places where traditional gardening would be impossible, like a kitchen counter or living room wall.

Even in the smallest system, you’ll see the amazing nitrogen cycle at work – fish produce waste containing ammonia, bacteria convert it to plant food (nitrates), and plants absorb these nutrients while cleaning the water that returns to the fish. It’s science in action right in your home!

Compact Aquaponic System Designs

When space is tight, choosing the right system design is super important. Here are the most popular options for small spaces:

1. Countertop Micro-Systems

These tiny systems use a small fish tank (usually 5-10 gallons) with a growing tray on top. They’re perfect for kitchens or small apartments where every inch counts. Countertop systems typically operate using either a small submersible pump or an air-lift pump system to move water from the fish tank to the growing area, creating a complete miniature ecosystem in as little as two square feet of space.

Pros:

• Takes up very little space
• Looks nice in your home
• Easy to take care of
• Perfect for growing herbs and small greens
• Great for teaching kids about ecosystems

Cons:

• Can only grow a few plants
• Only supports a couple of small fish
• Needs careful monitoring since small water volume changes quickly
• Usually needs extra lighting indoors

2. Vertical Wall-Mounted Systems

These clever systems use your wall space by mounting growing areas vertically, with the fish tank at the bottom. They’re a great way to transform your indoor space with a living wall that also produces food. Vertical wall systems can incorporate multiple growing techniques, from nutrient film technique (NFT) channels to pocket planters or tower designs, allowing you to maximize your growing area while minimizing floor space requirements.

Pros:

• Uses vertical space instead of floor space
• Creates a beautiful living wall effect
• Can grow quite a lot of plants
• Makes a stunning visual statement in your home

Cons:

• More complicated to set up
• May need to reinforce your wall
• Harder to maintain than simpler systems
• Costs more to get started

3. Balcony Systems

If you have a balcony, you can set up a slightly larger system using plastic totes or barrels. These provide more growing capacity while still fitting in a small outdoor space. Balcony systems often utilize the media bed method, where plants grow in clay pellets or similar media that is periodically flooded with nutrient-rich water from the fish tank below. This flood and drain cycle provides excellent oxygenation for plant roots and creates an ideal environment for beneficial bacteria.

Pros:

• Larger growing capacity than indoor systems
• More stable water conditions
• Can support more fish
• Relatively affordable to set up

Cons:

• Requires outdoor or balcony space
• Can be heavy (weight considerations for balconies)
• May need protection from weather
• Plumbing and components are visible

Fish Tank

Houses fish and serves as the nutrient source

Growing Area

Where plants thrive on fish-derived nutrients

Pump System

Circulates water between fish and plants

Bacterial Colony

Converts fish waste into plant-usable nutrients

Source: Go Green Aquaponics, 2025

Best Fish for Small Aquaponic Systems

Choosing the right fish is super important for small systems. You need fish that stay small, are hardy, and can handle living in limited space. The ideal fish species should be able to tolerate fluctuating conditions that are more common in small water volumes, while also producing sufficient waste to feed your plants without overwhelming the biological filtration capacity of your system.

Top Fish Choices for Tiny Systems:

1. Goldfish

Pros: Very hardy, can handle temperature changes, produce good waste for plants
Cons: Grow larger over time, might need a bigger home eventually

Common and comet goldfish are extremely resilient and can tolerate a wide range of water conditions, making them ideal for beginners. They produce abundant waste that’s rich in nutrients for plants, and they don’t require heaters in most indoor environments. However, be aware that they can grow up to 10-12 inches in optimal conditions, so you may eventually need to upgrade your system or rehome them.

2. Guppies and Small Livebearers

Pros: Colorful, breed easily, happy in small tanks
Cons: Produce less waste, so fewer plants can be supported

Guppies, platies, and mollies add vibrant colors to your system while staying small enough for countertop setups. These livebearers reproduce readily in captivity, giving you the fascinating opportunity to observe their life cycle. Their smaller size means they produce less waste than goldfish, so you’ll need to balance your plant selection accordingly, focusing on less nutrient-demanding species.

3. White Cloud Mountain Minnows

Pros: Can handle cooler water, school together nicely, stay small
Cons: Don’t produce as much waste as larger fish

These elegant, peaceful fish are excellent for unheated systems as they thrive in temperatures between 60-72°F (15-22°C). They typically grow to only 1.5 inches and display attractive schooling behavior, creating dynamic movement in your tank. Their metabolism is slower in cooler water, meaning they produce waste at a steadier, more manageable rate for small biological filtration systems.

4. Small Bettas

Pros: Beautiful, can live in smaller volumes, hardy
Cons: Males can’t be kept together, produce limited waste

Betta fish (also known as Siamese fighting fish) are stunning centerpieces for nano aquaponic systems with their flowing fins and vibrant colors. They’re labyrinth breathers, meaning they can take oxygen directly from the air, which provides an extra layer of security in small systems where oxygen levels might fluctuate. Each male betta requires its own tank, but females can sometimes be kept together in larger setups with careful monitoring.

For small systems, it’s important not to add too many fish. A good rule is 1 inch of fish per 5 gallons of water for micro systems (under 20 gallons). Putting too many fish in a small tank is the biggest mistake beginners make!

Note: The biggest mistake beginners make is overstocking small systems. Follow the recommended guidelines to maintain system health.

Best Plants for Small Aquaponic Systems

Choosing the right plants is just as important as picking the right fish. Some plants grow better than others in the limited space of a small aquaponic system. The ideal plant choices will depend on your system design, available light, and the nutrient output from your fish population.

1. Leafy Greens

Leafy greens are the workhorses of small aquaponic systems because they thrive in nitrogen-rich environments with relatively shallow root systems. Butterhead and romaine lettuce varieties are particularly well-suited to aquaponics, often growing faster than in soil gardens. For continuous harvests, you can practice “cut and come again” harvesting, where you take outer leaves while allowing the plant to continue growing from the center, extending your yield from a single planting.

Pros:

• Ready to harvest in just 3-4 weeks
• Great at removing nitrates from water
• Can be harvested a little at a time
• Don’t need deep roots
• Would cost a lot to buy at the store

Cons:

• Not as filling as fruiting plants
• May bolt (go to seed) if it gets too warm
• Some types need cooler temperatures

Best choices: Lettuce (all types), spinach, kale, Swiss chard, bok choy, arugula

2. Herbs

Herbs provide exceptional value in small aquaponic systems, as they’re typically expensive to purchase but easy to grow. Basil is particularly well-suited to aquaponics, often growing faster and more aromatic than soil-grown varieties. Different herbs have different light requirements – mint and parsley can tolerate partial shade, while basil and cilantro need more intense light. Regular harvesting of herbs stimulates bushier growth, increasing your overall yield and keeping plants from becoming leggy or flowering too quickly.

Pros:

• High value (herbs are expensive to buy)
• Can be harvested continuously
• Add flavor and nutrition to meals
• Compact growth habit
• Many keep growing for months or years

Cons:

• Some need specific temperatures
• May need trimming to prevent overgrowth
• Some can be picky about conditions

Best choices: Basil, mint, cilantro, parsley, chives, oregano, thyme

3. Compact Fruiting Plants

Fruiting plants require more nutrients and time than leafy greens, but they can be successfully grown in systems with established fish populations. Determinate (bush) varieties of cherry tomatoes like ‘Tiny Tim’ or ‘Micro Tom’ stay compact enough for small systems while still producing flavorful fruits. For indoor systems, you’ll need to assist with pollination by gently shaking flowering stems or using a small paintbrush to transfer pollen between flowers. Dwarf varieties of peppers like ‘Minibell’ or alpine strawberries are excellent choices that remain compact while producing sweet harvests.

Pros:

• More filling than leafy greens
• More variety in your harvest
• Look pretty while growing
• Worth more at the store

Cons:

• Take longer to produce food
• Need more nutrients
• May need help with pollination indoors
• Take up more space than greens

Best choices: Cherry tomatoes, strawberries, mini peppers, dwarf peas, bush beans

Setting Up Your Mini Aquaponic System

Setting up a small aquaponic system isn’t complicated if you follow these steps. The key is to plan carefully, select appropriate components, and allow enough time for the biological elements of the system to establish before expecting significant plant growth or adding fish.

Essential Equipment List

For a basic small-space system, you’ll need:

1. Fish tank: 10-50 gallons, depending on available space. Glass aquariums provide visibility and durability, while food-grade plastic containers offer affordability and lighter weight. Consider the tank’s footprint in relation to your available space, and ensure it’s placed on a stable, level surface that can support the weight (water weighs approximately 8.3 pounds per gallon).
2. Growing containers: Beds, channels, or floating rafts for plants. Media beds filled with expanded clay pellets provide excellent biological filtration and plant support. Floating raft systems work well for leafy greens, while NFT (Nutrient Film Technique) channels are ideal for herbs and compact plants with smaller root systems.
3. Water pump: 200-600 GPH, depending on system size. Select a submersible pump rated for continuous operation with energy efficiency in mind. As a general guideline, your pump should circulate the entire volume of your fish tank at least once per hour.
4. Air pump and stones: For fish and root oxygen. Oxygen is critical for fish health and bacterial function. In small systems, a dual-outlet aquarium air pump with ceramic air stones can adequately oxygenate both the fish tank and growing areas.
5. Plumbing: Food-grade PVC pipes and fittings. Use 1/2″ to 3/4″ PVC for small systems, ensuring all components are labeled as food-safe. Incorporate unions or disconnects in your plumbing design to facilitate maintenance and modifications.
6. Growing media: Clay pellets, lava rock, or similar (for media beds). These provide surface area for beneficial bacteria and physical support for plants. Expanded clay pellets (LECA) are lightweight and reusable, making them ideal for small systems.
7. Water testing kit: pH, ammonia, nitrite, nitrate tests. Regular testing is essential, especially in small systems where water parameters can change rapidly. Liquid test kits provide more accurate results than test strips, though they take slightly longer to use.
8. Timer: For pump cycling (if using flood and drain). Programmable digital timers allow precise control of flood and drain cycles, typically 15 minutes on followed by 45 minutes off for small media bed systems.
9. Lighting: If natural light is insufficient. For indoor systems, LED grow lights with full spectrum coverage provide energy-efficient illumination. Position lights 12-18 inches above plants and operate them for 12-16 hours daily, depending on plant requirements.

The Cycling Process

Before adding fish, you need to “cycle” your system – this means growing the beneficial bacteria that will convert fish waste into plant food. This takes 2-6 weeks and is the most important step! The nitrogen cycle establishes two critical bacterial populations: Nitrosomonas, which convert ammonia to nitrite, and Nitrobacter, which convert nitrite to plant-usable nitrate.

During cycling:

• Add dechlorinated water to your system. Tap water must be treated to remove chlorine and chloramine, which are toxic to beneficial bacteria. Use a commercial dechlorinator or let water sit for 24-48 hours to allow chlorine (but not chloramine) to dissipate.
• Add a source of ammonia (fish food or pure ammonia). For small systems, adding a pinch of fish food daily or dosing with 2-3 drops of pure ammonia (make sure it contains no additives or surfactants) per 10 gallons will provide the nutrients bacteria need to establish.
• Test water daily for ammonia, nitrite, and nitrate. Keep detailed records of your readings to track the cycling progress. You’ll first see ammonia rise, then nitrite, and finally nitrate as the bacterial colonies establish.
• Wait for ammonia and nitrite to spike and then drop to zero. This pattern indicates that both types of nitrifying bacteria have colonized your system in sufficient numbers. Be patient—rushing this process is the most common cause of system failures.
• When ammonia and nitrite read zero and nitrates are present, your system is cycled! This biological filtration is the heart of your aquaponic system and will maintain water quality for both fish and plants.

Only after cycling should you add a few hardy fish, and then gradually add plants. Monitor closely for the first month as the system stabilizes. Start with just 25% of your planned fish stocking level, adding more fish gradually over several weeks to allow the bacterial population to adjust to increasing waste production.