Dietary selenium (Se) is an essential component that supports fish growth and the immune system. This review attempts to provide insight into the biological impacts of dietary Se, including immunological responses, infection defense, and fish species growth, and it also identifies the routes via which it enters the aquatic environment. Dietary Se is important in fish feed due to its additive, antioxidant, and enzyme properties, which aid in various biological processes. However, excessive intake of it may harm aquatic ecosystems and potentially disrupt the food chain. This review explores the diverse natures of dietary Se, their impact on fish species, and the biological methods for eliminating excesses in aquatic environments. Soil has a potential role in the distribution of Se through erosion from agricultural, industrial, and mine sites. The research on dietary Se’s effects on fish immune system and growth can provide knowledge regarding fish health, fish farming strategies, and the health of aquatic ecosystems, promoting the feed industry and sustainable aquaculture. This review provides data and references from various research studies on managing Se levels in aquatic ecosystems, promoting fish conservation, and utilizing Se in farmed fish diets.

Aquaculture, the world’s fastest-growing food production sector, is critical for addressing food security concerns because of its potential to deliver high-quality, nutrient-rich supplies by 2050. This review assesses the effectiveness of CRISPR/Cas9 genome editing technology in enhancing desirable traits in fish species, including growth rates, muscle quality, disease resistance, pigmentation, and more. It also focuses on the potential effectiveness of the technology in allowing precise and targeted modifications of fish DNA to improve desirable characteristics. Many studies have reported successful applications of CRISPR/Cas9, such as knocking out reproductive genes to control reproduction and sex determination, enhancing feed conversion efficiency, and reducing off-target effects. Additionally, this technology has contributed to environmental sustainability by reducing nitrogen-rich waste and improving the nutritional composition of fish. However, the acceptance of CRISPR/Cas9 modified fish by the public and consumers is hindered by concerns regarding public perception, potential ecological impacts, and regulatory frameworks. To gain public approval and consumer confidence, clear communication about the editing process, as well as data on the safety and environmental considerations of genetically modified fish, are essential. This review paper discusses these challenges, provides possible solutions, and recommends future research on the integration of CRISPR/Cas9 into sustainable aquaculture practices, focusing on the responsible management of genetically modified fish to enable the creation of growth and disease-resistant strains. In conclusion, this review highlights the transformative potential of CRISPR/Cas9 technology in improving fish traits, while also considering the challenges and ethical considerations associated with sustainable and responsible practices in aquaculture.

The growing global interest in sustainable aquaculture has led to an increased search for alternatives to synthetic antibiotics and chemical feed additives. Medicinal plants have surfaced as promising ecological solutions, with research showing their potential to improve fish growth, boost immunity, and enhance disease resistance while decreasing the need for antibiotics. Recent studies suggest that supplementing fish diets with medicinal plants may improve survival rates. This supplementation upregulates key immune‐related gene responses, including cytokines such as interleukin (IL)‐1 β and tumor necrosis factor‐alpha (TNF‐ α ), as well as lysozyme (LYZ and LZM genes) and immunoglobulins (IgM, IgT, and IgD). As a result, innate and adaptive immune responses can be enhanced depending on the species and dosage. Furthermore, certain plant‐derived compounds have shown antimicrobial properties similar to traditional antibiotics, reducing pathogen loads by more than 50%. This review examines the role of medicinal plants in aquaculture, highlighting their effects on immunity, antimicrobial activity, and growth promotion. It delves into the mechanisms involved, such as the modulation of cytokine expression, enhancement of antioxidant defenses, and regulation of gut microbiota. However, challenges like variable phytochemical composition, the need for optimal dosages, and regulatory issues limit their broader use. While previous reviews have addressed the use of medicinal plants in aquaculture, few have thoroughly examined their dual role in both enhancing fish health and contributing to ecological functions such as improving water quality and promoting climate resilience. This review aims to fill that critical knowledge gap by integrating these dimensions highlighting how medicinal plants serve not only as bioactive growth promoters and immune enhancers but also as ecological tools for fostering environmental sustainability in aquaculture systems. Incorporating medicinal plants into aquaculture could potentially reduce antibiotic use by up to 50% by 2050, aligning with global efforts toward sustainable and eco‐friendly fish production. Innovations in phytochemical profiling, nanotechnology‐based delivery systems, and next‐generation sequencing are anticipated to further enhance the effectiveness and standardization of plant‐based aquafeeds. This comprehensive framework offers new insights into the development of resilient and environmentally responsible aquaculture practices, particularly in the face of climate change.

The common strain black carp (Cyprinus carpio var. baisenensis) is a culturally important carp strain that is raised and cultured in Guangxi Province, China. Its color reflects the interactions between the Burau people and their surrounding environment. The population of the common carp black strain was isolated and cultured in a rice-fish integration system. To explore the genetic diversity and protection of germplasm resources, we analyzed mitochondrial DNA (mtDNA) sequences, specifically the displacement loop (D-loop) and cytochrome b (Cytb), using single-nucleotide polymorphisms (SNP). We compared these sequences with those from four other local common carp populations. The study included a total of 136 adult common carps from five strain populations: the common black carp strain (HJ = 31), Jian (F = 30), Heilongjiang (H = 10), Songpu (S = 31), and Saijiang (SJ = 34). The results of the Cytb and D-loop analyses showed that the Heilongjiang carp (H) and Saijiang (SJ) populations had the highest levels of haplotype diversity (0.867 ± 0.034785) and nucleotide diversity (π = 0.0063 ± 0.000137 and 0.0093 ± 0.000411), respectively. On the other hand, the Common carp black strain population (HJ) exhibited the lowest haplotype diversity in both Cytb and D-loop, with haplotype 2 being the most commonly observed among the populations. Private haplotypes dominated the five common carp populations, which were significantly different at P<0.001. Furthermore, analyzing the coefficient of genetic differentiation (Fst), the highest genetic difference was observed between Saijiang (SJ) and Heilongjiang (H) (Fst = 0.963), whereas the lowest was observed between Songpu (S) and the Common carp black strain population (HJ) (Fst = 0.019) for the Cytb gene sequences. For the D-loop, the Common carp black strain population (HJ) and Songpu (S) (Fst = 0.7) had the highest values, and Heilongjiang (H) and Common black carp strain (HJ) had an Fst of 0.125. Additionally, the AMOVA analysis revealed a higher level of variance for the Cytb and D-loop genes, indicating lower genetic diversity within the local carp community. On the other hand, the phylogenetic tree analysis showed that the five carp populations were closely related and formed a distinct cluster. The distinct cluster of populations suggests a common ancestor or recent gene flow, possibly due to geographic proximity or migration history, and unique genetic characteristics, possibly due to adaptations or selective pressures. The results of this study provide valuable insights into the genetic diversity of the common strain black carp, which can have implications for conservation, breeding programs, evolutionary studies, and fisheries management.

Antibiotic use in aquaculture has become widespread to sustain production and control bacterial diseases, but it poses significant ecological and human health risks due to residue accumulation and resistance development. This study investigated the occurrence, dominance, and combined use of sulfonamide and fluoroquinolone antibiotics in freshwater fish aquaculture ponds around Wuxi, China. Here, the term aquaculture refers specifically to the controlled farming of freshwater fish species such as carp and crucian carp in managed pond systems. A total of 80 water samples (collected exclusively from pond waters) were obtained from 40 ponds during the high intensity rearing and harvest stage of fish. Residues of enrofloxacin and sulfonamide antibiotics were analyzed using a validated LC–MS/MS method with detection limits in the low nanogram-per-liter range. Results revealed that antibiotics were ubiquitous in pond waters, with enrofloxacin emerging as the dominant compound in August, reaching concentrations of up to 2.36 µg/L. By October, sulfonamides, particularly sulfamethoxazole and sulfadiazine, became more prevalent, with a maximum sulfadiazine concentration exceeding 4 µg/L. Multivariate analyses demonstrated a clear seasonal shift in antibiotic profiles, while correlation analyses indicated limited combined use in summer but notable co-occurrence of sulfonamides in autumn. These findings underscore that antibiotic application patterns in aquaculture are strongly linked to production stages, with potential consequences for environmental safety, resistance development, and food security. Effective monitoring, stricter regulation, and alternative disease management strategies are urgently required to mitigate risks and promote sustainable aquaculture practices.