Feeding Fish for Growth
Feeding for Growth: Matching Fish Food to Your Species & Stage
Feeding fish in an aquaponics system is more than dumping the cheapest food you can find into your system — it’s about optimizing growth, nutrient cycling, and plant health - which requires high-quality, nutritious, properly-size food. When you feed the right food to your fish, the entire system thrives.
Why Feeding Matters in Aquaponics
Feeding impacts more than your fish—it fuels your entire ecosystem. High-quality food leads to robust fish, enriched (beneficial) waste for plants, and balanced water chemistry. Poor diet? Risks include slow growth, unbalanced nutrient levels, and algae outbreaks.
Starter Stage: Fry
While we at Live Aquaponics do not recommend you start with fry, in the interest of being thorough we have included this section. Newly hatched fish need finely ground, nutrient-dense formulas. Think of them as little reactors: they grow quickly and generate waste that plants hunger for. For most fry our Fry Power (aka. Starter 100) is the perfect solution. If you are raising Tilapia you can also add Algae Wafers as an additional nutrient source, it will increase their growth rate, but it’s not required. Fry should be feed small portions six to ten times a day.
Fingerlings Stage
Once they reach about an inch, switch to a small, floating pellet that is approximately 1.4mm in size and rich in protein. This supports muscle development and helps maintain digestive health. We use and suggest our Starter 200. Fingerlings should be fed three to six times a day.
Grow-Out Stage
Once they reach about 3-4 inches, it’s time to move them up to Starter 300. Starter 300 is a floating pellet that is approximately 3.0mm in size. It is important not to move them to this food or any other food too soon. If a pellet is too large for a fish, you will see them take it into their mouth and spit in out, only to take it into their mouth again. This means the food size is too large and you should stay with the small size for a bit longer. The reason this is important is that many of the important nutrients (oils, vitamins, minerals, etc) are sprayed on commercial fish food after the pellets are formed. When the fish spit the food out, they lose important nutrients.
Adults and Breeders
Adult and breeder fish should be feed Starter 400. Starter 400 is a 4.8mm floating pellet. It has all the nutrients needed for continued growth and reproduction. Just like the other sizes of pellets, do not switch them too soon. Adults and breeders can be feed two to three times a day.
Non-Traditional Food Sources:
While commercial pellets are the gold standard for consistent nutrition, many aquaponics growers, aquaculturist and hobby fish keepers explore non-traditional food sources to reduce costs and increase sustainability. Options like Duckweed for Tilapia, Black Soldier fly larvae and worms for Bluegill, catfish and Hybrid Striped Bass, and even some kitchen vegetable scraps can supplement fish diets. These alternatives provide natural proteins, fats, and micronutrients, and they can be grown or raised on-site to create a closed-loop system. However, it’s important to balance them with formulated feed to ensure nutritional completeness, especially during rapid growth phases or breeding. Integrating these options thoughtfully can lower input costs and enhance the resilience of your system.
Feeding Techniques & Best Practices
- Feed small amounts multiple times a day — only feed the amount fish consume in about 3 minutes. Any food not consumed in that time should be removed immediately as it will negatively impact your water quality.
- Observe behavior — fish should be feeding aggressively. Once they slow down, stop feeding them.
- Adjust by conditions — fish eat less in cooler water, when stressed and if there are rapid water temperature or quality changes.
Monitoring Water Quality
Excess food decomposes, elevating ammonia and nitrites. Use your water test kit weekly to track pH, ammonia, nitrite, nitrate, and dissolved oxygen levels. If levels rise, reduce feed or improve filtration and aeration.
Tips for Transitioning Food Types
When changing pellet size or type, introduce it slowly over 2–3 days. Start by mixing a small amount with the current feed to allow fish to adapt and prevent digestive upset. Make sure you follow the guidelines above to ensure your fish are ready for the change.
Final Thoughts
Feeding your fish well is the core of a healthy aquaponics ecosystem. Matching diet type and size to species and growth stage means stronger fish, more plant-friendly waste, and fewer maintenance issues. Regular monitoring, careful feeding, and the right product choices make it all possible.