According to Gram Research analysis, largemouth bass can safely eat feed where up to 30% of traditional fish meal is replaced with crushed cockroach meal without slowing growth, and their muscle quality actually improves. A 2026 study of 450 fish found that 30% replacement maintained normal growth rates while improving muscle color and water retention, but replacing more than 30% caused liver damage and harmful changes to gut bacteria.
Scientists tested whether crushed cockroaches could replace traditional fish meal in the diet of largemouth bass—a popular farmed fish. In a 56-day study with 450 fish, researchers found that replacing up to 30% of fish meal with cockroach meal kept the fish healthy and actually improved their muscle quality and liver health. However, replacing more than 30% caused problems with the fish’s liver and changed their gut bacteria in unhealthy ways. This discovery could help fish farms find cheaper, more sustainable protein sources while maintaining fish quality.
Key Statistics
A 2026 controlled feeding trial with 450 largemouth bass found that replacing up to 30% of fish meal with cockroach meal maintained normal growth rates while improving muscle quality and liver antioxidant capacity.
In the same 56-day study, fish receiving 45% or higher cockroach meal replacement showed significant liver tissue damage and harmful shifts in intestinal bacteria composition, indicating a safe threshold exists at 30% replacement.
The research demonstrated that muscle from fish fed 30% cockroach meal replacement had better water-holding capacity and lighter color compared to fish eating traditional fish meal, suggesting improved meat quality for consumers.
The Quick Take
- What they studied: Whether crushed cockroach meal could safely replace traditional fish meal in the diet of farmed largemouth bass without harming the fish’s health or growth.
- Who participated: 450 largemouth bass fish weighing about 14.5 grams each at the start. The fish were divided into 5 groups that received different amounts of cockroach meal replacing their normal fish meal.
- Key finding: Fish that received up to 30% cockroach meal grew just as well as fish eating traditional food, and their muscle quality actually improved. But fish eating 45% or more cockroach meal showed signs of liver damage.
- What it means for you: Fish farms could potentially use cockroach meal as a cheaper, more sustainable protein source—but only up to 30% replacement. This could lower costs and reduce pressure on wild fish populations used for fish meal, though more research is needed before widespread use.
The Research Details
Researchers conducted a controlled feeding trial lasting 56 days with 450 largemouth bass fish. The fish were divided into five equal groups, with each group receiving a different diet. One group ate traditional fish meal (the control group), while the other four groups had increasing amounts of their fish meal replaced with crushed cockroach meal—15%, 30%, 45%, and 60% replacement rates.
Each diet group had three separate tanks with 30 fish in each tank, allowing researchers to compare results across multiple samples. The scientists measured how fast the fish grew, checked their liver health by looking at antioxidant levels (natural protective chemicals), examined their muscle quality, and analyzed the bacteria living in their intestines using genetic testing.
This design allowed researchers to identify the exact point where cockroach meal stops being beneficial and starts causing problems—a critical finding for practical fish farming applications.
This research approach is important because it tests a real-world farming scenario with realistic conditions. By using multiple tanks and measuring multiple health markers (growth, liver function, muscle quality, and gut bacteria), the researchers could identify both benefits and safety limits. This comprehensive approach helps fish farmers understand not just whether something works, but exactly how much they can safely use.
The study used a solid experimental design with multiple replicates (three tanks per diet group) and measured several important health markers. The 56-day duration is long enough to see meaningful changes in fish health. However, the study was conducted in a controlled laboratory setting, so results might differ in real farm conditions. The research was published in a peer-reviewed scientific journal, indicating it met professional standards for quality.
What the Results Show
Fish that received 30% or 45% cockroach meal replacement grew at the same rate as fish eating traditional fish meal, with no significant difference in weight gain. This is the key finding—it shows that cockroach meal can partially replace fish meal without slowing fish growth.
Muscle quality actually improved in all groups eating cockroach meal. The fish’s muscle was lighter in color and held water better, which are desirable traits in farmed fish. The fish’s livers also showed better antioxidant capacity (natural protective chemicals) when eating moderate amounts of cockroach meal, suggesting improved liver health.
However, when fish ate diets with 45% or more cockroach meal replacement, problems emerged. Their livers showed signs of damage, and their intestinal bacteria composition changed significantly in ways that suggest potential digestive problems. The 60% replacement group showed the most severe changes.
The intestinal bacteria analysis revealed important differences. Fish eating up to 30% cockroach meal had beneficial changes in their gut bacteria, with reductions in potentially harmful bacteria like Fusobacteriota. However, at higher replacement levels (45% and 60%), the bacterial community shifted dramatically, with increases in bacteria that could potentially cause problems. These bacterial changes suggest that very high cockroach meal levels stress the fish’s digestive system.
This research aligns with growing interest in alternative protein sources for aquaculture, as wild fish populations face pressure from overfishing. Previous studies have tested various insect meals in fish diets with mixed results. This study is notable because it identifies a specific safe threshold (30%) rather than simply testing whether an alternative works. The finding that muscle quality improves is particularly valuable, as it suggests cockroach meal could be both economical and beneficial.
The study was conducted in controlled laboratory conditions, so results may differ in actual fish farms with different water conditions or management practices. The research only tested one fish species (largemouth bass), so results may not apply to other farmed fish. The study lasted 56 days, which is moderate but may not reveal long-term effects. The paper doesn’t specify the exact nutritional composition of the cockroach meal used, which could affect how results apply to other cockroach meal sources. Finally, the study focused on fish health but didn’t evaluate the safety or nutritional quality of eating fish raised on cockroach meal from a human consumer perspective.
The Bottom Line
Fish farms can safely replace up to 30% of traditional fish meal with cockroach meal without harming fish growth or health—and may actually improve muscle quality (high confidence based on this controlled study). Replacing more than 30% is not recommended based on this research, as it causes liver damage and harmful changes to gut bacteria (high confidence). More research is needed before widespread commercial adoption, particularly in real-world farm conditions.
Fish farmers and aquaculture companies should care about this research, as it offers a potential cost-saving strategy. Environmental advocates interested in sustainable fishing should care, as reducing fish meal use could lower pressure on wild fish populations. Consumers of farmed fish may eventually benefit from lower costs and more sustainable farming practices. Researchers studying alternative proteins and insect-based feeds should use this as a foundation for further work.
The benefits observed in this study appeared within the 56-day trial period, suggesting that improvements in muscle quality and liver health could be seen relatively quickly in commercial settings. However, any commercial adoption would require additional testing in real farm conditions before seeing widespread implementation.
Frequently Asked Questions
Can fish farms use cockroach meal instead of fish meal?
Fish farms can safely replace up to 30% of fish meal with cockroach meal without harming fish growth. A 2026 study of 450 largemouth bass showed this replacement level actually improved muscle quality while maintaining normal growth rates.
What happens if you use too much cockroach meal in fish feed?
Replacing more than 30% of fish meal with cockroach meal causes liver damage and harmful changes to the fish’s gut bacteria, according to research testing replacement levels up to 60%. The damage increases with higher replacement percentages.
Does cockroach meal affect the quality of farmed fish meat?
Fish fed cockroach meal (up to 30% replacement) actually showed improved muscle quality with better color and water-holding capacity compared to fish eating traditional feed, making the meat potentially more desirable to consumers.
Why would fish farms want to use cockroach meal?
Cockroach meal could reduce costs for fish farms while being more sustainable than traditional fish meal, which comes from wild-caught fish. It also appears to improve the quality of the farmed fish without harming their health at appropriate replacement levels.
Is it safe to eat fish raised on cockroach meal?
This study focused on fish health, not human food safety. While the fish themselves remained healthy at 30% replacement, additional research would be needed to confirm the safety and nutritional quality of eating fish raised on cockroach meal.
Want to Apply This Research?
- For aquaculture professionals: Track the percentage of fish meal replaced in your feed formulation (0-30% recommended) and monitor corresponding changes in fish growth rate, muscle quality metrics, and liver health markers weekly.
- If using this research to adjust farm practices: Gradually transition to 30% cockroach meal replacement in your feed while monitoring fish health indicators. Document growth rates, feed conversion efficiency, and any visible health changes to verify results match this study.
- Establish a baseline of current fish health metrics before implementing cockroach meal, then track weekly measurements of growth rate, muscle quality (color and water retention), and liver enzyme levels. Set alerts if any metric deviates significantly from expected ranges, indicating the replacement percentage may need adjustment.
This research was conducted on largemouth bass in controlled laboratory conditions and may not apply to other fish species or real-world farm environments. The study evaluated fish health but did not assess the safety or nutritional quality of consuming fish raised on cockroach meal from a human food safety perspective. Anyone considering implementing cockroach meal in aquaculture operations should conduct additional testing in their specific conditions and consult with aquaculture specialists and regulatory authorities. This summary is for informational purposes and should not be considered professional agricultural or veterinary advice.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.