By: Karen A. Chagwaya
Abstract: Fish farming has increasingly emerged as a viable strategy for enhancing food security, improving nutrition, creating employment opportunities, and strengthening livelihood resilience in arid and semi-arid areas (ASALs). However, the success and sustainability of aquaculture systems in these regions are highly dependent on the quality of water available for fish production. Water quality influences fish growth, metabolism, feed conversion efficiency, reproduction, disease resistance, and survival, making it one of the most critical determinants of aquaculture productivity. Arid and semi-arid environments are characterized by water scarcity, high evaporation rates, elevated temperatures, salinity accumulation, and increasing climate variability, all of which pose significant challenges to sustainable fish farming. This article reviews the relationship between water quality and aquaculture production, with particular emphasis on the key physicochemical and biological parameters that influence fish health and productivity. The paper further examines the impacts of poor water quality on fish welfare, explores emerging technologies for water quality management, and discusses sustainable strategies for promoting aquaculture development in water-constrained environments. The review demonstrates that effective water quality management is fundamental to achieving sustainable aquaculture production and enhancing food security in arid and semi-arid regions.
Keywords: Water quality parameters, aquaculture water parameters, fish farming in ASALs, arid and semi-arid lands economic activities, fish health, biofloc technology, aquaponics, sustainable aquaculture.
1. Introduction
Aquaculture has become one of the fastest-growing food production sectors worldwide and is increasingly recognized as a critical pathway for enhancing food security, improving nutrition, reducing poverty, and supporting sustainable economic development. The sector has gained global prominence due to rising demand for fish and fish products, declining capture fisheries, population growth, urbanization, and increasing awareness of the nutritional benefits of aquatic foods (World Health Organization [WHO], 2023). According to the Food and Agriculture Organization (FAO, 2024), aquaculture currently contributes more than half of the aquatic animal products consumed globally, making it a vital component of contemporary food systems. Beyond its contribution to food production, aquaculture supports livelihoods through employment creation, income generation, and value chain development, particularly in low- and middle-income countries. The sector also contributes to the achievement of several Sustainable Development Goals (SDGs), including those related to food security, poverty reduction, economic growth, and environmental sustainability (Alcamo, 2019). Consequently, fish farming is increasingly viewed not merely as a source of animal protein but as a strategic tool for promoting socio-economic development and strengthening resilience among vulnerable populations (Boyd, 2017; FAO, 2024; WHO, 2023).
The relevance of aquaculture is particularly evident in arid and semi-arid lands (ASALs), where recurrent droughts, erratic rainfall, land degradation, and declining agricultural productivity continue to threaten livelihoods and food security. In these environments, fish farming offers a promising alternative for livelihood diversification and climate adaptation due to its potential to generate income, enhance dietary diversity, and utilize water resources more efficiently when properly managed. However, the sustainability and productivity of aquaculture systems in ASAL regions depend heavily on water quality, which directly influences fish growth, metabolism, reproduction, immunity, feed conversion efficiency, and survival. Water quality parameters such as temperature, dissolved oxygen, pH, salinity, turbidity, and ammonia determine the suitability of aquatic environments for fish production and significantly affect overall farm performance (Boyd, 2017; Demeke & Tassew, 2016; Devi et al., 2017). Poor water quality has been associated with reduced growth rates, disease outbreaks, physiological stress, increased mortality, and economic losses, while climate change-induced challenges such as rising temperatures, water scarcity, salinity accumulation, and increased evaporation are further exacerbating water quality concerns in ASAL aquaculture systems (Alcamo, 2019; Mohammad & Haque, 2021; Sampaio & Freire, 2016). Therefore, understanding the relationship between water quality and fish farming is essential for developing sustainable aquaculture systems capable of enhancing food security, environmental sustainability, and livelihood resilience in arid and semi-arid regions.
- Concept of Water Quality in Aquaculture
Water quality refers to the physical, chemical, and biological characteristics of water that determine its suitability for sustaining aquatic organisms and supporting productive aquaculture systems (Zhang et al., 2025). In aquaculture, water functions not merely as a habitat but also as the medium through which essential physiological, biochemical, and ecological processes occur. Fish rely on water for respiration, feeding, digestion, osmoregulation, reproduction, waste excretion, and movement, making water quality a fundamental determinant of fish health and productivity. Consequently, parameters such as temperature, dissolved oxygen, pH, salinity, turbidity, ammonia, alkalinity, hardness, nutrient concentrations, microbial communities, and pollutant levels collectively influence the performance and sustainability of aquaculture operations (Devi et al., 2017; Verma et al., 2022; Leonard & Mahengea, 2022). Because fish are continuously exposed to the aquatic environment, any alteration in water quality can rapidly affect physiological functions, growth rates, feed utilization efficiency, disease resistance, and survival (Demeke & Tassew, 2016).
The significance of water quality in aquaculture extends beyond maintaining fish survival to directly influencing production efficiency, profitability, fish welfare, and environmental sustainability. Studies have consistently demonstrated that optimal water quality conditions promote higher growth rates, improved feed conversion efficiency, enhanced reproductive performance, and greater resistance to diseases, while poor water quality contributes to physiological stress, behavioral abnormalities, reduced productivity, and increased mortality (Boyd, 2017; Mohammad & Haque, 2021; Mramba & Kahindi, 2023). Zhang et al. (2025) further reported that water quality significantly influences fish behavior, affecting swimming activity, feeding responses, social interactions, and stress-related behaviors that ultimately determine production outcomes. Similarly, Omoregie (2023) observed that water quality enhancement remains one of the most critical requirements for achieving sustainable freshwater fish production in Africa, particularly in regions experiencing increasing environmental and climatic pressures.
Water quality in aquaculture should be understood as a dynamic and interconnected system rather than a collection of independent environmental variables. Physical, chemical, and biological parameters interact continuously, creating complex ecological relationships that influence fish performance and ecosystem functioning. For example, elevated water temperatures increase metabolic rates and oxygen demand while simultaneously reducing dissolved oxygen availability and increasing ammonia toxicity. Likewise, fluctuations in pH affect nutrient availability, microbial activity, and the toxicity of nitrogenous compounds, thereby influencing fish health and productivity (Boyd, 2017; Devi et al., 2017; Verma et al., 2022). Otoo et al. (2019) demonstrated that interactions among water quality variables significantly influence fish yields in pond aquaculture systems, emphasizing the importance of integrated water quality management approaches. These findings highlight the need for holistic monitoring frameworks capable of capturing the complex interactions that occur within aquaculture ecosystems.
The growing intensification of aquaculture production has further increased the importance of water quality management. Intensive production systems are characterized by high stocking densities, increased feed inputs, and elevated production targets, all of which contribute to greater accumulation of organic wastes, nutrients, and metabolic by-products. Without effective management, these conditions may result in oxygen depletion, ammonia accumulation, eutrophication, and increased disease risks (Tian & Dong, 2023; Rajesh et al., 2024; Boyd, 2017). Tschikof (2018) demonstrated that nitrogen cycling processes play a critical role in maintaining environmental stability within integrated recirculating aquaculture systems, while Rajesh et al. (2024) emphasized that successful operation of recirculating aquaculture systems depends on rigorous control of water quality parameters. As aquaculture continues to transition toward more intensive and resource-efficient production systems, maintaining optimal water quality has become increasingly essential for ensuring productivity, profitability, and sustainability.
The relationship between water quality and fish health has received considerable attention within aquaculture research due to its implications for disease prevention and fish welfare. Poor water quality conditions weaken immune function, increase physiological stress, impair growth, and create favorable conditions for the proliferation of pathogens. Demeke and Tassew (2016) reported that many disease outbreaks in aquaculture systems are closely associated with environmental stressors arising from poor water quality management. Similarly, Mramba and Kahindi (2023) found significant relationships between pond water quality, fish yields, and disease occurrence in aquaculture systems located in arid environments. Zhang et al. (2025) further observed that fish behavioral changes often serve as early indicators of deteriorating water quality, suggesting that behavioral monitoring can complement conventional water quality assessment methods. These findings reinforce the importance of preventive water quality management as a strategy for enhancing fish health and minimizing disease-related production losses.
Water quality management has also become increasingly important from an environmental sustainability perspective. The expansion and intensification of aquaculture have raised concerns regarding nutrient loading, organic pollution, wastewater discharge, eutrophication, and degradation of aquatic ecosystems. Ojewole et al. (2024) emphasize that effective wastewater management is essential for reducing environmental impacts and promoting sustainable aquaculture development. Similarly, Mawundu et al. (2023) reported that aquaculture activities can alter nutrient concentrations and trophic conditions in surrounding water bodies, highlighting the need for environmentally responsible production practices. Sustainable aquaculture therefore requires management approaches that simultaneously optimize fish production, protect water resources, and minimize ecological degradation (Alcamo, 2019; Ojewole et al., 2024; Mawundu et al., 2023).
The importance of water quality management is particularly pronounced in arid and semi-arid areas where water scarcity, high evaporation rates, salinity accumulation, and climate variability create additional environmental challenges. In such regions, maintaining suitable water quality conditions is often complicated by limited opportunities for water exchange and increasing competition for freshwater resources. Leonard and Mahengea (2022) observed that water quality conditions in aquaculture ponds are strongly influenced by local environmental characteristics and management practices, while Omoregie (2023) identified water quality enhancement as a prerequisite for sustainable freshwater aquaculture development across Africa. Furthermore, limnological investigations of African aquatic ecosystems have demonstrated that nutrient dynamics, water chemistry, and ecological processes significantly influence the suitability of water bodies for fish production (Niyoyitungiye, 2019). These findings suggest that sustainable aquaculture development in ASAL regions will require innovative water management technologies, continuous monitoring, and adaptive management strategies capable of addressing emerging environmental challenges.
2.1 Key Water Quality Parameters Affecting Fish Production
Water quality parameters determine the suitability of the aquatic environment for fish growth, reproduction, health, and survival. These parameters influence physiological processes such as respiration, metabolism, osmoregulation, nutrient utilization, and immune function. Since fish are continuously exposed to their surrounding environment, any alteration in water quality can have immediate consequences on fish behavior, welfare, productivity, and profitability. Table 1 presents the generally accepted optimal water quality ranges for major cultured freshwater fish species.
Table 1: Recommended Water Quality Ranges for Common Cultured Fish Species
| Parameter | Nile Tilapia | African Catfish | Common Carp | Rainbow Trout |
| Temperature (°C) | 25–30 | 26–32 | 20–28 | 10–18 |
| Dissolved Oxygen (mg/L) | >5 | >4 | >5 | >6 |
| pH | 6.5–8.5 | 6.5–8.5 | 6.5–9.0 | 6.5–8.0 |
| Total Ammonia (mg/L) | <0.05 | <0.05 | <0.05 | <0.02 |
| Nitrite (mg/L) | <0.1 | <0.1 | <0.1 | <0.05 |
| Nitrate (mg/L) | <100 | <100 | <100 | <50 |
| Salinity (ppt) | 0–15 | 0–10 | 0–8 | 0–5 |
| Alkalinity (mg/L CaCO₃) | 50–200 | 50–200 | 50–200 | 20–150 |
| Hardness (mg/L CaCO₃) | 50–300 | 50–300 | 50–300 | 40–200 |
| Transparency (cm) | 30–60 | 30–60 | 30–60 | Clear water |
Water Temperature
Water temperature is a fundamental water quality parameter that directly influences fish physiology, behavior, growth, reproduction, and overall aquaculture productivity. As ectothermic organisms, fish depend on ambient water temperatures to regulate metabolic processes, making temperature one of the primary determinants of biological performance in aquaculture systems. Optimal temperature conditions enhance feed intake, nutrient assimilation, enzymatic activity, and growth, whereas temperatures outside species-specific tolerance ranges can suppress appetite, impair reproductive functions, increase susceptibility to diseases, and reduce survival rates. Studies conducted in aquaculture ponds have demonstrated that temperature significantly influences fish production outcomes and interacts closely with other environmental variables affecting water quality and ecosystem productivity (Otoo et al., 2019; Mramba & Kahindi, 2023). Furthermore, limnological investigations of African aquatic ecosystems indicate that temperature plays an important role in regulating biological productivity, nutrient dynamics, and ecological stability, all of which influence the suitability of aquatic environments for fish culture (Niyoyitungiye, 2019).
The significance of temperature is particularly evident in arid and semi-arid regions where high solar radiation, prolonged dry periods, and elevated evaporation rates frequently alter pond conditions. Research from small-scale aquaculture systems has shown that increasing temperatures may contribute to reduced fish yields and higher disease occurrence due to their influence on metabolic stress and water quality deterioration (Mramba & Kahindi, 2023). Similarly, Leonard and Mahengea (2022) observed that temperature variations significantly affect pond water quality characteristics and can influence overall production performance. Temperature also affects oxygen availability, nutrient cycling, and microbial activity within aquaculture systems, thereby influencing ecosystem functioning and fish health (Otoo et al., 2019; Omoregie, 2023). As climate change continues to increase the frequency of heat stress events and alter hydrological conditions, effective temperature management through improved pond design, shading, aeration, and water circulation will become increasingly important for sustaining aquaculture productivity in water-constrained environments (Omoregie, 2023; Tian & Dong, 2023; Rajesh et al., 2024).
Dissolved Oxygen
Dissolved oxygen is one of the most important indicators of water quality because it directly supports fish respiration, energy production, growth, and survival. Adequate oxygen concentrations are necessary for maintaining normal physiological functions, efficient feed conversion, immune competence, and overall fish welfare. In aquaculture systems, dissolved oxygen levels influence productivity by determining the capacity of aquatic environments to sustain healthy fish populations. Studies have consistently shown that low dissolved oxygen concentrations are associated with reduced growth rates, poor feed utilization, increased physiological stress, and elevated disease risks (Mramba & Kahindi, 2023; Leonard & Mahengea, 2022). Investigations of pond water quality dynamics further reveal that dissolved oxygen is among the most influential factors affecting fish yield because of its close relationship with biological productivity, nutrient cycling, and ecosystem health (Otoo et al., 2019).
The concentration of dissolved oxygen within aquaculture systems is influenced by several interacting factors, including temperature, photosynthesis, respiration, organic matter decomposition, stocking density, and water movement. In arid and semi-arid regions, high temperatures often reduce oxygen solubility while simultaneously increasing metabolic oxygen demand among cultured fish, creating conditions that can compromise fish health and productivity (Omoregie, 2023; Mramba & Kahindi, 2023). Nutrient enrichment and accumulation of organic wastes may further increase biological oxygen demand, thereby accelerating oxygen depletion and increasing environmental stress. Sustainable management of dissolved oxygen therefore requires integrated approaches that combine water quality monitoring, proper stocking densities, waste management practices, and the use of technologies such as aeration systems, biofloc production systems, and recirculating aquaculture systems. These innovations have been shown to improve oxygen availability, enhance nutrient utilization, and increase production efficiency while minimizing environmental impacts (Ojewole et al., 2024; Tian & Dong, 2023; Rajesh et al., 2024; Tschikof, 2018).
pH
The pH of water is an important indicator of acidity and alkalinity and plays a central role in regulating biological, chemical, and ecological processes within aquaculture systems. Most freshwater fish species perform optimally within a pH range of 6.5–8.5, although tolerance limits vary depending on species, life stage, and environmental conditions. Appropriate pH levels promote nutrient availability, microbial activity, metabolic efficiency, and overall fish health, while extreme acidic or alkaline conditions can adversely affect growth and survival (Boyd, 2017; Verma et al., 2022). Studies on aquaculture pond dynamics have shown that pH influences primary productivity and interacts with other water quality variables to determine overall pond performance (Otoo et al., 2019). Similarly, assessments of fish ponds in East Africa revealed that maintaining stable pH conditions is essential for sustaining favorable environmental conditions and supporting aquaculture productivity (Leonard & Mahengea, 2022).
The importance of pH extends beyond fish physiology because it influences the behavior, availability, and toxicity of numerous chemical compounds within aquatic environments. In particular, pH affects the proportion of toxic un-ionized ammonia present in water, with elevated pH levels increasing toxicity risks to cultured fish (Boyd, 2017; Tschikof, 2018). Prolonged exposure to unsuitable pH conditions can damage gill tissues, disrupt osmoregulatory functions, suppress immune responses, and increase disease susceptibility, ultimately reducing fish yields and farm profitability (Demeke & Tassew, 2016; Mramba & Kahindi, 2023). In arid and semi-arid regions, evaporation, mineral accumulation, and fluctuating water chemistry may further contribute to pH instability, necessitating regular monitoring, liming, buffering, and integrated water quality management practices to maintain suitable production environments (Omoregie, 2023; Ojewole et al., 2024).
Ammonia and Nitrogenous Compounds
Ammonia is among the most significant pollutants affecting aquaculture systems because it is continuously generated through fish excretion, decomposition of uneaten feed, microbial degradation of organic matter, and other biological processes occurring within production environments. Although ammonia is a natural component of aquatic ecosystems, excessive accumulation can severely compromise fish health, water quality, and production efficiency. Nitrogenous waste levels are often influenced by stocking density, feeding practices, water exchange rates, and waste management effectiveness, making ammonia an important indicator of overall farm management performance (Verma et al., 2022; Boyd, 2017). Research conducted in freshwater pond systems has shown that excessive nutrient accumulation contributes to declining water quality and reduced fish productivity, while effective nitrogen management supports healthier and more productive aquaculture systems (Mohammad & Haque, 2021; Otoo et al., 2019).
The toxicity of ammonia is strongly influenced by temperature and pH, with higher temperatures and alkaline conditions increasing the concentration of toxic un-ionized ammonia. Exposure to elevated ammonia levels may impair respiration, damage gill tissues, suppress feeding activity, weaken immunity, and increase susceptibility to disease outbreaks (Demeke & Tassew, 2016; Verma et al., 2022). Studies in arid-region aquaculture systems have further demonstrated significant relationships between nitrogen accumulation, disease occurrence, and reduced fish yields (Mramba & Kahindi, 2023). Recent advances in water quality management have introduced innovative approaches such as biofloc systems, biological filtration, wastewater treatment technologies, and recirculating aquaculture systems that improve nitrogen utilization and reduce environmental pollution. These technologies have been shown to enhance nutrient recycling, improve water quality stability, and support sustainable aquaculture production under conditions of increasing water scarcity (Emerenciano et al., 2017; Tschikof, 2018; Tian & Dong, 2023; Ojewole et al., 2024).
Turbidity and Water Transparency
Turbidity refers to the cloudiness of water caused by suspended particles such as sediments, plankton, organic matter, and microorganisms, while transparency describes the extent to which light penetrates through the water column. These parameters significantly influence photosynthesis, primary productivity, oxygen generation, and ecological balance within aquaculture systems. Moderate turbidity can support plankton production and natural food availability, whereas excessive turbidity may reduce light penetration and limit biological productivity (Boyd, 2017; Verma et al., 2022). Studies examining pond water quality dynamics have shown that transparency levels are closely associated with fish production and ecosystem functioning because they influence phytoplankton abundance and nutrient cycling processes (Otoo et al., 2019). Limnological studies have similarly demonstrated that light availability plays a critical role in determining aquatic productivity and fish-carrying capacity (Niyoyitungiye, 2019).
Excessive turbidity may negatively affect fish health by reducing visibility, impairing feeding efficiency, irritating gill tissues, and increasing physiological stress. Poor water clarity has also been associated with reduced growth rates, lower feed utilization efficiency, and increased vulnerability to disease, particularly in systems experiencing excessive sedimentation or nutrient enrichment (Demeke & Tassew, 2016; Leonard & Mahengea, 2022). In addition, aquaculture activities and nutrient loading can alter trophic conditions and water clarity in aquatic ecosystems, highlighting the importance of managing suspended solids and organic matter accumulation (Mawundu et al., 2023). Effective turbidity management through erosion control, sedimentation structures, pond maintenance, and regular monitoring therefore contributes significantly to improved water quality, enhanced fish performance, and sustainable aquaculture development, particularly in environmentally fragile and water-limited regions (Omoregie, 2023; Ojewole et al., 2024).
Salinity
Salinity refers to the concentration of dissolved salts present in water and is an important factor influencing fish physiology, osmoregulation, growth, and survival. Although many aquaculture species are adapted to specific salinity ranges, significant deviations from these conditions may induce physiological stress and compromise production performance. Demeke and Tassew (2016) emphasize that maintaining salinity within acceptable limits is essential for promoting fish health and ensuring successful aquaculture operations.
Fish continuously regulate the movement of water and dissolved salts across their body surfaces to maintain internal physiological balance. Changes in salinity affect these osmoregulatory processes and may increase energy expenditure. As more energy is allocated to maintaining osmotic balance, less energy becomes available for growth, reproduction, and immune function. Boyd (2017) notes that prolonged exposure to unsuitable salinity conditions often results in reduced feed conversion efficiency and lower production performance.
Salinity management is particularly important in arid and semi-arid regions where high evaporation rates and groundwater mineralization frequently increase salt concentrations. Water scarcity may further exacerbate salinity challenges by limiting opportunities for dilution and water replacement. Alcamo (2019) highlights that increasing water scarcity and environmental degradation are likely to intensify water quality challenges, including salinity accumulation, in many vulnerable regions. Such trends underscore the need for proactive salinity management strategies.
Although elevated salinity can pose significant challenges, certain fish species exhibit considerable tolerance to moderately saline environments. Appropriate species selection therefore represents an important adaptation strategy for aquaculture development in ASAL regions. The use of salinity-tolerant species, combined with effective water quality monitoring and management, can enhance production resilience and improve sustainability in water-constrained environments (Boyd, 2017; Demeke & Tassew, 2016).
Sustainable salinity management requires integrated approaches that combine efficient water use, regular monitoring, appropriate species selection, and improved resource management practices. Such strategies can help minimize production risks while supporting the long-term viability of aquaculture systems operating under increasingly challenging environmental conditions.
Alkalinity and Hardness
Alkalinity and hardness are important chemical properties of water that contribute significantly to ecosystem stability, fish health, and aquaculture productivity. Alkalinity refers to the capacity of water to neutralize acids and resist sudden changes in pH, while hardness is determined by the concentration of dissolved minerals, particularly calcium and magnesium. These parameters influence water chemistry, nutrient availability, microbial activity, and the overall suitability of aquatic environments for fish culture. Appropriate alkalinity levels enhance the buffering capacity of water, thereby stabilizing pH and supporting biological productivity, while adequate hardness provides essential minerals required for physiological functions and normal fish development (Boyd, 2017; Verma et al., 2022). Studies investigating pond water quality dynamics have demonstrated that balanced alkalinity and hardness contribute to favorable environmental conditions that support fish growth, plankton productivity, and overall aquaculture performance (Otoo et al., 2019; Leonard & Mahengea, 2022).
The significance of alkalinity and hardness extends beyond water chemistry because these parameters directly affect fish physiology and resilience to environmental stress. Calcium and magnesium play critical roles in bone formation, osmoregulation, enzyme activation, muscle function, and metabolic regulation, while adequate alkalinity helps maintain stable environmental conditions necessary for optimal fish performance. Fish cultured in waters with extremely low hardness may experience reduced growth rates, impaired physiological functioning, and increased susceptibility to stress and disease (Demeke & Tassew, 2016; Verma et al., 2022). In arid and semi-arid environments, alkalinity and hardness often fluctuate due to groundwater composition, mineral accumulation, evaporation, and changing hydrological conditions, sometimes resulting in concentrations that exceed desirable limits for aquaculture production (Niyoyitungiye, 2019; Omoregie, 2023). Consequently, routine monitoring, liming where appropriate, and integrated water quality management practices are essential for maintaining balanced water chemistry, enhancing fish welfare, and supporting sustainable aquaculture development under varying environmental conditions (Mramba & Kahindi, 2023; Ojewole et al., 2024).
2.2 Water Quality and Fish Health
Fish health is intrinsically linked to the quality of the aquatic environment because water serves as the medium through which respiration, feeding, osmoregulation, reproduction, and waste excretion occur. Consequently, any deterioration in water quality can directly affect physiological functioning, growth performance, immune competence, and survival. Research has consistently demonstrated that poor water quality is among the leading causes of stress, disease outbreaks, reduced productivity, and mortality in aquaculture systems (Demeke & Tassew, 2016; Verma et al., 2022). Studies conducted in aquaculture ponds have further shown that fish yield and disease occurrence are strongly influenced by water quality conditions, with poorly managed systems generally experiencing lower production and higher disease prevalence than systems maintained within recommended environmental limits (Mramba & Kahindi, 2023; Mohammad & Haque, 2021). In addition, assessments of fish ponds in Africa have highlighted the importance of maintaining stable physicochemical conditions to support healthy fish populations and sustainable aquaculture development (Leonard & Mahengea, 2022; Omoregie, 2023).
The relationship between water quality and fish health extends beyond physiological effects to include behavioral responses and overall welfare. Environmental stress resulting from low dissolved oxygen, excessive ammonia, inappropriate pH, elevated temperatures, or organic pollution can disrupt homeostasis, suppress immune responses, impair growth, and increase vulnerability to bacterial, fungal, and parasitic infections (Sampaio & Freire, 2016; Demeke & Tassew, 2016). Recent studies have shown that fish often exhibit behavioral changes such as reduced feeding activity, abnormal swimming patterns, surface gasping, and social disruption when exposed to unfavorable water quality conditions, making behavior an important indicator of fish welfare and environmental quality (Zhang et al., 2025). Similarly, Yavuzcan Yildiz et al. (2017) emphasize that fish welfare is closely associated with water quality because environmental conditions influence both physiological and behavioral outcomes. Therefore, maintaining optimal water quality is not only essential for maximizing production but also for ensuring fish welfare, disease prevention, and long-term aquaculture sustainability.
2.3 Emerging Water Quality Management Technologies
Biofloc Technology
Biofloc technology (BFT) has emerged as one of the most innovative and sustainable approaches for improving water quality in aquaculture systems. The technology relies on beneficial microbial communities that convert dissolved nitrogenous wastes into microbial biomass, which can subsequently be consumed by fish as a supplementary protein source. This process improves nutrient utilization efficiency while simultaneously reducing the accumulation of harmful metabolites within culture water. Studies have shown that biofloc systems contribute to improved water quality, enhanced feed conversion efficiency, increased production capacity, and reduced environmental impacts compared to conventional aquaculture systems (Emerenciano et al., 2017; Tian & Dong, 2023). Furthermore, biofloc technology supports the development of more intensive production systems by maintaining favorable environmental conditions even under relatively high stocking densities.
One of the most significant advantages of biofloc technology is its ability to improve nitrogen management through microbial assimilation of ammonia and other nitrogenous compounds. Excessive ammonia accumulation remains one of the primary causes of water quality deterioration in aquaculture systems; however, biofloc microorganisms convert these compounds into microbial protein, thereby reducing toxicity risks and improving environmental stability (Emerenciano et al., 2017; Tschikof, 2018). The technology is particularly suitable for arid and semi-arid regions because it requires minimal water exchange, thereby conserving scarce water resources while maintaining high production efficiency. Given increasing concerns regarding water scarcity, environmental sustainability, and climate resilience, biofloc technology is increasingly recognized as a practical solution for supporting sustainable aquaculture development in water-limited environments (Omoregie, 2023; Ojewole et al., 2024).
Aquaponics Systems
Aquaponics is an integrated production system that combines aquaculture and hydroponic crop cultivation within a symbiotic environment where fish and plants mutually benefit from nutrient recycling processes. In these systems, nutrient-rich fish waste is utilized as a fertilizer source for plants, while plant roots and associated microorganisms remove excess nutrients from the water before it is returned to the fish culture unit. This integrated approach enhances resource-use efficiency, improves water quality, and promotes sustainable food production by simultaneously producing fish and crops within the same system (Medina et al., 2016; Yavuzcan Yildiz et al., 2017). As a result, aquaponics has gained increasing attention as a climate-smart and environmentally sustainable aquaculture technology.
The capacity of aquaponic systems to improve water quality is largely attributable to nutrient recycling and biological filtration processes. Studies have demonstrated that aquaponics effectively reduces nutrient accumulation, improves water clarity, enhances biological productivity, and minimizes environmental pollution by utilizing fish wastes that would otherwise accumulate within the production system (Medina et al., 2016). Ulya et al. (2021) further reported that aquaponic systems can contribute to the removal of heavy metals and improve nutrient utilization efficiency, thereby enhancing overall water quality and environmental sustainability. These characteristics make aquaponics particularly suitable for arid and semi-arid regions where efficient water utilization is critical. By producing fish and vegetables simultaneously while minimizing water consumption, aquaponics contributes to food security, income diversification, and climate resilience among farming communities facing increasing water scarcity (Omoregie, 2023; Ojewole et al., 2024).
Probiotics in Water Quality Management
The use of probiotics has emerged as an important biological strategy for improving water quality, enhancing fish health, and reducing disease risks in aquaculture systems. Probiotics consist of beneficial microorganisms that improve microbial balance within culture environments, suppress harmful pathogens, enhance nutrient cycling, and contribute to the decomposition of organic wastes. Unlike chemical treatments, probiotics provide an environmentally friendly approach to water quality management by promoting natural biological processes that improve environmental stability and fish welfare. Research has shown that probiotic applications can improve growth performance, feed utilization efficiency, survival rates, and overall productivity in aquaculture systems while simultaneously reducing the occurrence of disease outbreaks (Elsabagh et al., 2018; Omoregie, 2023).
Beyond their direct effects on fish health, probiotics contribute significantly to water quality improvement by reducing the accumulation of organic matter and harmful metabolites within aquaculture environments. Beneficial microbial populations accelerate the breakdown of waste products, improve nutrient recycling, and help maintain favorable physicochemical conditions for fish production. Elsabagh et al. (2018) reported that Bacillus-based probiotics improved water quality, blood parameters, intestinal morphology, and growth performance in Nile tilapia culture, demonstrating the multifaceted benefits of probiotic applications. Furthermore, probiotics reduce dependence on antibiotics and chemical treatments, thereby supporting environmentally sustainable aquaculture practices and contributing to healthier production systems. As aquaculture continues to intensify, the integration of probiotics into water quality management programs offers significant potential for improving productivity, environmental sustainability, and fish welfare across diverse production systems.
3. Conclusion
This review established that water quality is the foundation of successful and sustainable aquaculture production, particularly in arid and semi-arid regions where water scarcity and environmental variability present significant challenges to fish farming. The review demonstrated that key water quality parameters including temperature, dissolved oxygen, pH, ammonia, turbidity, salinity, alkalinity, and hardness play critical and interconnected roles in influencing fish growth, health, behavior, reproduction, welfare, and overall productivity. Maintaining these parameters within optimal ranges is essential for promoting efficient feed utilization, minimizing physiological stress, reducing disease occurrence, and enhancing production performance. The review further highlighted that deteriorating water quality contributes significantly to reduced fish yields, increased mortality, poor feed conversion efficiency, and environmental degradation. Emerging technologies such as biofloc systems, aquaponics, probiotics, and recirculating aquaculture systems were identified as effective approaches for improving water quality, enhancing resource-use efficiency, and supporting sustainable aquaculture development. As aquaculture continues to expand in response to growing demand for fish and fish products, effective water quality management will remain central to achieving productive, resilient, and environmentally sustainable fish farming systems.
Based on the findings, fish farmers should prioritize routine monitoring of water quality parameters and adopt appropriate management practices that maintain stable and favorable aquatic conditions throughout the production cycle. Greater emphasis should be placed on the adoption of innovative and water-efficient technologies capable of improving water quality while reducing environmental impacts and conserving scarce water resources. Governments, research institutions, and development partners should strengthen farmer training, extension services, and technical support programs aimed at improving water quality management and promoting sustainable aquaculture practices. Investment in climate-smart aquaculture technologies, water conservation strategies, and environmentally responsible production systems should also be enhanced to address the growing challenges associated with climate change and water scarcity. Additionally, future research should focus on developing locally appropriate and cost-effective water quality management solutions that can enhance aquaculture productivity and sustainability in arid and semi-arid environments. Such efforts will contribute significantly to improved food security, income generation, environmental conservation, and livelihood resilience among communities engaged in fish farming.
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