In aquaponics, fish aren’t just pets; they’re the driving force behind your entire system. The type of food you give them not only affects how quickly they grow, but also how healthy your plants will be. Every pellet or flake you feed eventually cycles back into your system as nutrients for your vegetables, herbs, and fruits. That’s why choosing the right fish food for aquaponics systems is so important.

In this blog, we’ll look at what to feed some of the most common aquaponics fish, including tilapia, catfish, trout, koi, and more. Whether you’re setting up your first small system or scaling up a backyard farm, understanding your fish’s diet will help you keep your water clean, your fish healthy, and your plants thriving.

And if you want to go even deeper, this 5-hour premium aquaponics video course covers fish nutrition, feeding schedules, and system management in much greater detail. It’s the next step if you’re serious about building a thriving system.

The Connection Between Fish Food and System Success

Everything is connected in aquaponics, and fish food sits at the heart of that connection. What goes into your fish  will come out as waste, and that waste is converted by beneficial bacteria into nutrients your plants can use. If the food is not right for your fish, the entire balance of your system can be thrown off.

• Good fish food equals healthy fish.Fish that get the right balance of protein, fats, and vitamins grow faster, resist disease better, and live longer.
• Healthy fish equals clean, nutrient-rich water. The waste they produce is easier for bacteria to process when their diet is correct.
• Nutrient-rich water equals thriving plants.Strong, steady nutrient availability leads to faster plant growth and better harvests.

Think of it this way: your aquaponics system is a cycle, and fish food is the spark that keeps it turning. Skimping on food quality or using the wrong type can lead to problems like ammonia spikes, poor fish growth, or stunted plants.

Key Factors in Choosing Fish Food for Aquaponics

Here are the main factors to consider when selecting fish food for your aquaponics system:

1. Fish Species and Dietary Needs

Different fish eat different diets. Tilapia, for example, are omnivores and do well with both plant-based and protein-rich feeds, while catfish need higher protein levels to thrive. Always start by matching the food to your species.

2. Pellet Size and Type

• Floating pellets are great for surface feeders like tilapia.
• Sinking pellets are better for bottom feeders like catfish.
  Choosing the right pellet type reduces waste and ensures your fish actually eat what you provide.

3. Protein Content

• Fry and fingerlings (baby fish) need higher protein to grow quickly.
• Adults often thrive on lower-protein diets, which helps cut feed costs.

4. Additional Nutrients

Look for feeds that also contain vitamins, minerals, and healthy fats. These keep fish strong and reduce the risk of disease outbreaks.

5. Sustainability and Cost

Commercial fish feed can be expensive, but it’s consistent and reliable. Many aquaponics growers also explore sustainable options like duckweed or black soldier fly larvae to supplement pellets.

Common Aquaponics Fish and Their Diet

1. Tilapia

Tilapiaare the most popular fish for aquaponics systems. They grow quickly, tolerate a wide range of water conditions, and aren’t picky eaters. But that doesn’t mean you can feed them just anything. Giving tilapia the right diet helps them grow faster, stay healthier, and provide your plants with a steady stream of nutrients.

Tilapia Diet Basics:

• Omnivores: Tilapia naturally eat both plants and small aquatic animals.
• Protein needs by stage:
• Fry (baby fish):35–40% protein for rapid growth.
• Fingerlings:30–35% protein.
• Adults: 28–32% protein is usually enough.

Commercial Feed for Tilapia

• Look for floating pellets (since tilapia are surface feeders).
• Choose high-quality feed with balanced vitamins and minerals.
• Avoid cheap livestock feed, which lacks the right nutrients and can damage water quality.

Supplemental Food Options

• Duckweed or Azolla:Fast-growing aquatic plants tilapia love.
• Vegetable scraps:Spinach,lettuce, or kale (in small amounts).
• Insects: Black soldier fly larvae or worms for added protein.

Why This Matters in Aquaponics

Tilapia that get the right mix of protein and supplements not only grow better but also produce waste that’s easier for bacteria to process. That means cleaner water and healthier plants.

2. Catfish

Catfish are another excellent choice for aquaponics systems. They grow large, adapt well to various climates, and are popular in many regions as a food fish. But unlike tilapia, catfish have slightly different feeding habits and dietary requirements.

Catfish Feeding Basics:

• Diet Type: Catfish are primarily carnivorous but adapt well to formulated feeds.
• Protein Needs:
• Fry and fingerlings: 35–40% protein.
• Adults:28–32% protein, depending on growth goals.
• Pellet Preference:Many catfish prefer sinking pellets, since they are bottom dwellers.

Commercial Feed for Catfish

• Choose feeds with higher protein for younger catfish, shifting to lower protein as they grow.
• A balanced pellet with added vitamins and minerals helps reduce disease risk.
• Floating pellets can also be used if you want to monitor feeding more closely.

Supplemental Feeding Options

• Insects and Worms:Earthworms or black soldier fly larvae provide a natural protein boost.
• Small Fish or Crustaceans: Some systems allow supplemental live food, though this may not be practical for beginners.

Why This Matters in Aquaponics

Catfish are big eaters. Overfeeding them with the wrong food can lead to uneaten pellets sinking to the bottom, where they rot and cause ammonia spikes. Getting the balance right is critical to keeping both fish and plants healthy.

3. Trout

Trout  are cold-water carnivores known for rapid growth and high protein requirements, making them a top choice in cooler regions.

Feeding Basics:

• Carnivorous, requiring a high-protein diet.
• Thrive in cool water environments.
• Need frequent feeding during active growth periods.

Commercial Feed

• High-protein floating or slow-sinking pellets (40–45% protein).
• Look for feeds formulated for cold-water species.

Supplemental Feeding Options

• Insects, worms, or small crustaceans can enhance their diet.
• Not recommended to rely heavily on DIY feed since trout are sensitive to diet changes.

Why It Matters

Trout grow quickly but are less forgiving than tilapia or catfish. Their high protein requirements and cooler temperature needs make them ideal for growers in colder climates who can commit to a stricter feeding program.

4. Koi and Goldfish (Ornamental Species)

Koi and goldfish are hardy ornamental species. They won’t end up on your dinner plate, but their consistent waste output and resilience make them perfect for decorative or beginner-friendly systems.

Feeding Basics:

• Omnivorous, with a preference for plant-based foods.
• Lower protein needs (25–30%).
• Hardy and easy to care for, making them perfect for small or decorative systems.

Commercial Feed

• Floating pellets designed for koi and goldfish.
• Available in a wide range of pellet sizes for different fish ages.

Supplemental Feeding Options

• Vegetables such as lettuce, spinach, or peas.
• Small amounts of worms or insect larvae.

Why It Matters

Koi and goldfish don’t grow as large as tilapia or catfish, and they’re often chosen for ornamental aquaponics systems where aesthetics matter. While they won’t provide much food for your table, their waste still supports plant growth, making them a great option for beginners or small indoor systems.

5. Barramundi

Barramundi  are fast-growing warm-water fish prized for their firm, white flesh. They thrive in larger, well-managed systems.

Feeding Basics:

• Carnivorous, fast-growing, and suited for warm climates.
• Require a high-protein diet similar to trout.

Commercial Feed

• Floating pellets with 40–45% protein.
• Look for feeds specifically formulated for carnivorous warm-water fish.

Supplemental Feeding Options

• Small fish, shrimp, or insects can boost protein intake.
• Some growers experiment with black soldier fly larvae as a supplement.
  

Why It Matters

Barramundi are excellent food fish with rapid growth rates, but they can be aggressive feeders. Managing their diet correctly ensures healthy growth while preventing water quality issues from leftover feed.

6. Small Ornamental Fish (Betta, Guppies, Mollies, Tetras)

Small ornamental fish  like bettas, guppies, mollies, and tetras are ideal for indoor or desktop aquaponics setups. While they don’t produce food, they’re easy to care for and provide excellent educational opportunities.

Feeding Basics:

• Typically omnivorous or insectivorous.
• Much smaller food requirements compared to tilapia or catfish.
• Best suited for indoor aquaponics systems like desktop setups or classroom models.

Commercial Feed

• Specialized tropical fish pellets or flakes.
• Choose high-quality brands with balanced vitamins to avoid nutrient deficiencies.

Supplemental Feeding Options

• Live or frozen foods like brine shrimp or bloodworms.
• Tiny amounts of vegetable matter (blanched spinach or peas) for omnivorous species like guppies or mollies.

Why It Matters

Small ornamental fish won’t provide a food harvest, but they’re fantastic for educational and decorative aquaponics systems. Their lower waste output is perfect for growing small herbs or leafy greens indoors. They’re also low-maintenance and a fun way to introduce kids to aquaponics.

DIY and Sustainable Fish Food Options

Fish feed is one of the largest recurring costs in an aquaponics system. While commercial pellets provide balanced nutrition, many growers supplement or replace store-bought feed with DIY and sustainable fish food alternatives to save money and reduce reliance on outside inputs.

1. Insect-Based Feeds

a. Black Soldier Fly Larvae (BSFL)

• High in protein and healthy fats.
• Can be farmed at home with food scraps, making them cost-effective and eco-friendly.
• Suitable for tilapia, catfish, and carnivorous species like trout or barramundi.

b. Mealworms and Earthworms

• Great protein-rich supplements.
• Easy to raise in small bins.
• Often used as treats rather than staple feed.

2. Plant-Based Feeds

• Duckweed:  Duckweed is afast-growing aquatic plant rich in protein (up to 40%). Tilapia and koi readily eat it.
• Azolla: Another floating fern that grows quickly and adds nitrogen to water.
• Vegetable Scraps: Leafy greens, peas, and spinach can supplement omnivorous fish diets.

3. Homemade Pellet Mixes

Some growers create their own pellets using:

• Fish meal or soybean meal (for protein).
• Wheat, rice bran, or corn (for energy).
• Vitamins and minerals for balanced nutrition.

Feeding Schedules and Best Practices

Feedingyour fish isn’t just about what they eat it’s also about when and how you feed them. Overfeeding is one of the most common mistakes beginners make in aquaponics, and it can quickly lead to poor water quality, plant stress, and even fish deaths.

1. General Feeding Guidelines

• 2–3 times per day: Most species do well with small, frequent feedings.
• 5–10 minutes rule:  Only give as much food as your fish can consume within 5–10 minutes. Remove uneaten food to protect water quality.
• Adjust by age:
• Fry (baby fish): Require frequent, small feedings throughout the day.
• Juveniles:  2–3 times daily with higher protein content.
• Adults: 1–2 times daily, with stable feed portions.

2. Seasonal and Temperature Adjustments

• Warm-water species (e.g., tilapia, catfish, koi):  Eat more in warmer months when metabolism is higher.
• Cool-water species (e.g., trout): Feed more actively in cooler conditions and less during heat.
• Winter dormancy: In colder climates, some fish naturally slow their metabolism and may need very little food.

3. Signs of Overfeeding

• Uneaten food floating at the surface or collecting at the bottom.
• Cloudy water and increased ammonia levels.
  Fish showing sluggish behavior due to poor water quality.

4. Best Practices for Success

• Feed consistently:  Stick to a regular schedule.
• Observe your fish: Watch how eagerly they feed. Appetite changes are often the first sign of stress or illness.
• Balance diet and waste:  Remember, fish food isn’t just for the fish, it also drives nutrient production for your plants.

Why Feeding Schedules Matter

A well-managed feeding routine keeps your fish healthy, your plants supplied with steady nutrients, and your system balanced. Too much or too little food can disrupt the entire ecosystem.

Sample Feeding Schedules for Common Aquaponics Fish

Fish Species	Age/Stage	Frequency	Portion Size	Notes
Tilapia	Fry (0–2 months)	4–5 times/day	Tiny amounts of finely ground feed	High protein (35–40%); ensure steady growth.
	Juvenile (2–6 months)	2–3 times/day	What they consume in 5–10 min	Can begin introducing supplemental feed (duckweed, BSFL).
	Adult (6+ months)	1–2 times/day	What they consume in 10 min	Lower protein (28–32%) is acceptable.
Catfish	Fry	4–5 times/day	Very fine starter feed	Sensitive to poor water quality, don’t overfeed.
	Juvenile	2–3 times/day	5–10 min consumption	High-protein pellets for fast growth.
	Adult	1–2 times/day	10 min consumption	Prefer sinking feed; avoid floating waste.
Trout	Fry	5–6 times/day	Fine, high-protein feed	Cold-water species; appetite varies with temperature.
	Juvenile	3–4 times/day	5–10 min consumption	Maintain high protein (40–45%).
	Adult	2 times/day	10 min consumption	Adjust feed during hot weather (reduced appetite).
Koi & Goldfish	Juvenile	2–3 times/day	Small floating pellets	Supplement with veggies.
	Adult	1–2 times/day	Moderate pellets	Lower protein diets (25–30%).
Small Ornamentals (Betta, Guppies, Mollies, Tetras)	Juvenile	2–3 times/day	Tiny flakes/pellets; consumed in seconds	Supplement with occasional live/frozen food.
	Adult	1–2 times/day	Small amounts, avoid overfeeding	Ideal for indoor/desktop aquaponics setups.

Common Mistakes to Avoid in Feeding Aquaponics Fish

Even with the best intentions, beginners often make simple feeding mistakes that can lead to poor fish health, stunted plant growth, or system crashes. Knowing these pitfalls ahead of time will save you time, money, and frustration.

1. Overfeeding

• The mistake: Feeding more than fish can eat, leading to uneaten food rotting in the system.
• The consequence:Spikes in ammonia and nitrite, poor water quality, plant stress, and possible fish deaths.
• How to avoid it:Stick to the 5–10 minute rule and adjust based on fish activity.

2. Using the Wrong Type of Feed

• The mistake: Feeding trout pellets to tilapia, or giving ornamental flakes to food fish.
• The consequence:Nutritional deficiencies, slow growth, and wasted money.
• How to avoid it:Always match feed type and protein content to your specific fish species.

3. Ignoring Water Temperature and Seasonal Changes

• The mistake:Feeding fish the same amount all year round.
• The consequence: Fish may refuse food or the system may build up uneaten waste during colder months.
• How to avoid it:Learn how your fish’s metabolism changes with water temperature.

4. Relying Too Heavily on DIY Feeds

• The mistake:Feeding only duckweed or kitchen scraps.
• The consequence:Nutrient imbalances, poor fish growth, and weak plant production.
• How to avoid it:Use DIY feeds as supplements, not total replacements, unless you’ve carefully balanced the diet.

5. Inconsistent Feeding Schedules

• The mistake:Skipping days or feeding at random times.
• The consequence:Fish stress, uneven growth, and disrupted nutrient flow to plants.
• How to avoid it: Stick to a routine that fits both your fish and your lifestyle.

6. Ignoring Warning Signs

• The mistake: Not paying attention when fish suddenly lose appetite.
• The consequence:Missed early signs of disease, stress, or water quality problems.
• How to avoid it:Observe feeding behavior closely,it’s often the first red flag something is wrong.

Conclusion

Feeding your fish isn’t just about keeping them alive, it’s about building the foundation of your entire aquaponics system. The right diet leads to:

• Healthy, fast-growing fish 
• Strong, nutrient-rich plants 
• A balanced, thriving ecosystem 

From choosing the right commercial feed to experimenting with DIY supplements like duckweed and black soldier fly larvae, each decision you make shapes how productive your system will be.

We’ve covered the basics in this guide:

• What to feed species like tilapia, catfish, trout, koi, and even small ornamentals
• How to balance commercial vs. supplemental feeds
• Why feeding schedules and best practices matter
• The common mistakes beginners must avoid

But here’s the truth: aquaponics feeding is never one-size-fits-all. Your fish, climate, and system design all play a role.

If you’re serious about aquaponics and want to avoid trial-and-error frustration, this 5-hour premium aquaponics video course is the next step.

Whether you’re raising tilapia for food or koi for beauty, this course gives you the confidence to feed your fish right  and grow a system that thrives.