Recirculating Aquaculture Systems (RAS) are complex and costly projects that require deep technical expertise and precise engineering. Mistakes made at the design or construction stage often result in massive financial losses, reduced efficiency, and in some cases — complete failure of the farm.

In this article, we review the most common mistakes in RAS aquaculture projects and explain how to avoid them.

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1. Lack of Feasibility Study (Business and Technical Analysis)

Mistake: starting the construction of a fish farm without conducting a proper market analysis, feasibility study, or financial model.

Consequences: the farm may prove unprofitable — either there is no stable demand for the product, or the production cost is higher than the market price.

How to avoid: conduct a comprehensive market study before construction, including demand, competition, pricing, and a full business plan.

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2. Wrong Choice of Aquaculture Species

Mistake: choosing the fish species based on personal preference rather than market demand and biological requirements.

Consequences:

• Lack of stable market demand.
• Biological risks: unknown diseases, slow growth, high mortality.
• Very few specialists available to solve species-specific problems.

How to avoid: always start with a market analysis. Select proven species with existing technologies, established demand, and available expertise.

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3. Mistakes in Selecting Location, Water Supply, and Energy Infrastructure

Mistake: choosing land based on low price or convenience while ignoring water supply, energy needs, logistics, and staffing.

Consequences:

• Excessive costs for infrastructure and utilities.
• Lack of space for wastewater treatment, sludge management, or evaporation ponds.
• In marine aquaculture — problems with saline water disposal.
• Insufficient groundwater or unstable water sources → farm cannot reach designed capacity.
• Seasonal water fluctuations in quality and temperature → stress and fish mortality.
• Risk of losing access to water due to urban development or land-use changes.
• Heating with electricity in warm-water RAS → unsustainable operational costs.
• Poor logistics: difficult transport of fingerlings and fresh product.
• Lack of available workforce → staffing problems and turnover.

How to avoid:

• Verify water quality, flow rate, and stability of the source (well or surface water).
• Ensure long-term reliability — avoid seasonal or legal risks.
• Implement a wastewater discharge system approved by local authorities.
• For warm-water fish farms, use natural gas as the main heating source (electricity is too costly).
• Consider logistics: access roads, distance to markets, processing facilities.
• Evaluate workforce availability and provide on-site housing for staff if needed.

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4. Errors in Thermal Balance of Cold-Water RAS

Mistake: incorrect calculation of thermal balance or poor insulation. In many cases, operators try to maintain low water temperatures with increased water exchange.

Consequences:

• Continuous increase in make-up water requirement.
• Biofilter instability due to high water turnover.
• Overloaded discharge systems.
• High operational costs from excess water consumption.

How to avoid: calculate a precise thermal balance and ensure proper insulation of the facility. Use chillers, geothermal cooling, or advanced insulation materials instead of relying on water exchange.

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5. Mistakes in Biofiltration Design

Mistake: purchasing so-called “universal biofilter systems” that are not designed for the specific fish species.

Consequences:

• Biofilter cannot properly remove ammonia (NH₃/NH₄⁺).
• Farm cannot reach projected production density.
• Increased fish mortality and financial losses.

How to avoid: biofiltration must be calculated for each project based on fish species (carnivores, herbivores, cannibalistic species, cold-water or warm-water). Work only with engineering companies that provide custom RAS design instead of standard kits.

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6. Neglecting Automation and Monitoring

Mistake: reducing costs by avoiding automation.

Consequences:

• High dependence on human staff.
• Delayed reaction to system failures → mass fish mortality.

How to avoid: install monitoring systems for dissolved oxygen, pH, temperature, and ammonia. Use automated alarms, redundancies, and backup systems.

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7. Poor Ergonomics and Facility Layout

Mistake: designing the system without considering operational convenience.

Consequences:

• Maintenance becomes complex and time-consuming.
• Higher risk of human error and accidents.
• Reduced overall efficiency of the fish farm.

How to avoid: design with operators in mind. Optimize tank placement, workflows, and access routes for equipment, staff, and fish handling.

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8. Lack of Step-by-Step Commissioning

Mistake: launching the entire RAS facility at full capacity from day one.

Consequences:

• Problems and design flaws discovered too late.
• High mortality of fish during the first cycle.

How to avoid: introduce gradual commissioning — start with small biomass, stabilize the biofilter, test systems, and only then scale up.

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9. Underestimating the Human Factor

Mistake: relying only on technology and ignoring the role of staff.

Consequences: even the best RAS systems fail due to untrained or careless operators.

How to avoid: train employees, hire aquaculture specialists with real RAS experience, and create a culture of responsibility and preventive maintenance.

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Conclusion

Mistakes in RAS aquaculture design and construction can cost millions. Most failures are not caused by technology, but by poor planning: wrong species choice, unsuitable location, unreliable water or energy supply, or lack of trained staff.

By avoiding these common mistakes and relying on professional aquaculture engineering, investors and operators can significantly increase the success rate of their projects.

💡 Contact me to get a free initial consultation and learn how to avoid these mistakes in your fish farming project: Contact Aquaculture Engineer

© Dmitry Yakovlev