1 Introduction

Snakehead fish (Channa spp.), members of the order Perciformes and family Channaidae, are freshwater predatory fish named for their snake-like heads. Unlike most fish, they breathe air, a rare physiological trait. Their distribution range is extremely wide, extending from South Asia to several countries and regions in East Asia, including a closely related group, the Parachanna, in Africa (Huang et al., 2022).

Currently, approximately 50 different species of snakehead fish have been documented, most of which are found in Asia (Britz et al., 2024). They can survive in various water types, tolerate low oxygen environments, and can crawl short distances on land. Some populations have become invasive in various regions after being introduced by humans into non-native habitats (Zhou et al., 2022). Snakehead fish are considered important top predators in freshwater ecosystems (Britz et al., 2020).

Blackfish species have strong adaptability and can survive in extreme environments such as hypoxia, dry water bodies, high or low temperatures. For example, many Channa spp. have developed auxiliary respiratory organs (often referred to as suprabranchial organs or air-breathing structures) that can directly breathe air, allowing them to survive in polluted and hypoxic water bodies or even during short periods of drought or desiccation (Ou et al., 2021; Han et al., 2025). These special adaptations make Channa spp. one of the ideal models for studying the evolution of fish environmental adaptability. In recent years, with the development of molecular systematics and genomics, a large number of research results on the evolutionary biology of the blackfish genus have emerged continuously (Ou et al., 2021; Britz et al., 2024). Traditionally, the classification and evolutionary relationships of species in the genus Blackfish are mainly inferred based on morphological characteristics, but identification confusion and classification disputes caused by morphological similarities between different species have long existed (Praveenraj et al., 2020; Htoo et al., 2025).

Modern phylogenetic studies, combining mitochondrial DNA, nuclear gene sequences, and biogeographic data, supplemented by molecular clock estimates, have successfully reconstructed the evolutionary trajectory of Chinese snakehead fish (Britz et al., 2020; Prazhnikov, 2023). The introduction of whole-genome sequencing has provided a new approach for analyzing the genetic characteristics of key species. Furthermore, the continuous accumulation of multi-omics data is driving in-depth systematic studies of the mechanisms of adaptive evolution (Ou et al., 2021; Han et al., 2025). Certain functional genes have undergone rapid evolution in expression regulation, and this change is highly correlated with their unique ecological habits (Laskar et al., 2023).

This study will systematically review multiple dimensions of research on the genus Blackfish, evaluate species diversity patterns and taxonomic controversies, analyze the main progress in molecular phylogenetic reconstruction, and explore the role of geological events in shaping lineage differentiation; At the same time, focusing on genomics research results, analyzing the genetic basis of key traits such as hypoxia adaptation and immune evolution; And compare the convergent adaptation cases of different ecological types of species. This study constructs a comprehensive framework for the adaptive evolution of the blackfish genus, providing a theoretical basis for subsequent conservation biology and evolutionary research.

2 Overview and Current Taxonomic Status of the Genus Channa

2.1 Species diversity and geographic distribution of the genus Channa

The species diversity of the blackfish genus is high, and it is distributed in tropical, subtropical, and temperate regions of Asia. The geographical distribution range of each species varies greatly (Britz et al., 2020; Zhou et al., 2022). Traditional taxonomy has recorded about 35 species of Channa fish based on morphological characteristics, but in recent years, with the deepening of investigations in remote areas and the application of molecular identification methods, a large number of new species have been discovered and described, bringing the total number of species to around 50 (Britz et al., 2020; Htoo et al., 2025). For example, in Southeast Asia and South Asia, multiple new species have been announced in recent years: four new species of the Channa genus have been discovered in the Western Ghats Mountains of India (Praveenraj et al., 2019); New dwarf Channa spp. species have also been discovered in the border areas of Yunnan, China and Myanmar (Zhang et al., 2024).

The natural distribution of Channa is concentrated in three major geographical regions: East Asia, Southeast Asia, and South Asia. There are several well-known species distributed in East Asia, such as the Channa argus in northeastern China and eastern Russia, as well as the Channa asiatica in southern China. Southeast Asia is the region with the richest species of snakehead fish. Large species such as Channa micropeltes, Channa marulius and Channa striata widely inhabit the Péninsule Indochine and the Malay Islands (Figure 1). A new species, Channa shingon, has been discovered in the surrounding areas of Yunnan and Myanmar (Britz et al., 2020; Htoo et al., 2025).

There are also numerous endemic species in South Asia, such as the Channa Stewart in northeastern India and the Channa kelaartii in Sri Lanka (Praveenraj et al., 2020). The eastern foothills of the Himalayas are particularly rich in small and narrowly distributed species, making it a biodiversity hotspot for black fish. About 40% of the species in the snakehead genus are only distributed in this area. In contrast, the three species of snakehead in Africa belong to the Parachanna genus, which diverged from the Asian snakehead genus in ancient times (late Paleozoic to early Cenozoic). From the distribution range, they are completely isolated from the Asian snakehead genus (Britz et al., 2020).

2.2 Controversies and issues in taxonomy and nomenclature

Snakehead species are remarkably similar in appearance, posing a long-standing challenge to their classification and identification (Praveenraj et al., 2020; Htoo et al., 2025). Researchers generally rely on body coloration and morphological features to distinguish snakeheads, but this method can be less accurate when these features overlap between species. Some "new species" named based on their morphology were found to be invalid after genetic testing and should be incorporated into existing species. For example, the recently described dwarf species C. shingon in the Channa genus in Myanmar was initially confused with its closely related species C. rubricacia, but its validity was later determined by combining morphology and COI sequences (Zhang et al., 2024). For example, the C. kelaartii, which is unique to Sri Lanka, was long considered a variant of the widely distributed C. gachua. A 2019 study re established the effective species status of C. kelaartii through molecular evidence, solving a 146 year long classification puzzle (Praveenraj et al., 2020).

2.3 Current status of phylogenetic research

The relationships among different snakehead fish species have long been a focus of research. Early studies primarily relied on a small number of mitochondrial genes (Pamenter et al., 2020). In recent years, technological advances have led to a greater diversity of research methods. Scientists have begun utilizing richer genomic information (e.g., COI, cytochrome b) and nuclear genes (e.g., RAG1, rhodopsin genes) to improve the reliability of phylogenetic signals (Britz et al., 2024). Furthermore, the application of technologies such as RAD-seq and whole-genome sequencing has enabled more refined phylogenetic reconstructions (Ou et al., 2021).

Britz et al. (2020) conducted a study on large snakehead fish that lasted for over three years. They analyzed approximately 5kb of genetic material and classified the snakehead fish into 8 major groups based on their habitat. The northern group is represented by the Argus group, while the southern group includes the Asiatica group. There are three groups in Southeast Asia: Striata, Lucius, and Gachua. The main groups in South Asia are Marulius and Punctata (Britz et al., 2020; Huang et al., 2022). This is basically consistent with the classification method of scientists based on appearance in the past, but there are also some differences. Some small "dwarf" snakehead fish with similar appearances are not actually close relatives (Britz et al., 2020).

3 Phylogenetic Reconstruction of Snakeheads and Species Evolution

3.1 Molecular markers and phylogenetic analysis methods

The molecular markers used for the phylogenetic reconstruction of the Blackfish genus mainly include mitochondrial genes and nuclear genes, each with its own advantages and disadvantages. Mitochondrial DNA, due to its high mutation rate, maternal monophyletic inheritance, and easy amplification, is a commonly used marker in fish systematics, such as COI, Cyt b, 16S rRNA, etc., which are widely used in the classification and identification of black fish (Praveenraj et al., 2020; Zhang et al., 2024). Nuclear genes provide parental genetic information, with representative markers including the first recombinant kinase gene (RAG1), nuclear 28S rRNA, and actin introns. These nuclear sequences evolve at a slower rate, but can reflect deeper divergence events. To balance information from different evolutionary levels, recent studies have often adopted a multi gene joint strategy, such as linking mitochondrial gene sequences with nuclear sequences such as RAG1 and Rh protein gene fragments for analysis, in order to improve the robustness of the phylogenetic tree (Britz et al., 2020; Britz et al., 2024).

In terms of analysis methods, Bayesian inference (BI) and maximum likelihood (ML) are currently the mainstream methods for constructing phylogenetic trees. By selecting appropriate replacement models and hyperparameters, a highly reliable system topology can be obtained. Zhang et al. (2024) constructed COI gene trees using both BI and ML methods when studying a new species of Burmese dwarf snakehead, and both methods consistently clustered the new species into monophyletic branches. In addition, molecular systematics also utilizes some auxiliary methods. For example, using BEAST software for simultaneous inference of molecular clocks and phylogenetic trees, node ages can be directly annotated on the system tree; Using population genetic methods such as STRUCTURE to validate the corresponding cryptic units of system branches (Praveenraj et al., 2020); And explore the possible effects of hybridization and gene flow on system relationships through network analysis.

3.2 Phylogenetic tree construction results and major lineage divisions

The new DNA analysis provides a more precise molecular basis for the classification of snakehead fish (Britz et al., 2020; Britz et al., 2024). One group lives in northern areas. This includes fish like Channa argus and Channa asiatica. They're mostly found in East Asia's cooler waters. The family tree shows these fish from northern China and the Yangtze River are closely related. The South Asian branch includes large species such as Channa punctata and Channa marulius, forming independent branches on the phylogenetic tree (Britz et al., 2020). These large fish species are concentrated in the river and lake systems of the South Asian subcontinent, and there are significant differences in habitat preferences and morphological characteristics compared to Southeast Asian groups. Its typical ecological characteristics include a preference for open water environments and adaptation to still or slow-moving habitats in plain areas.

Southeast Asian subfamily (Gachua group, Lucius group, Micropeltes group, Striata group, etc.): This represents the most diverse and evolutionarily successful clade within the genus Channa, including numerous small and medium-sized species, distributed in Thailand, Indochina Peninsula, Malay Archipelago, and other places. The Gachua group includes many dwarf snakeheads with a body length of only over ten centimeters, such as C. gachua and C. andro, which are rich in species and mostly distributed in narrow areas (Bhardwaj et al., 2022). The Lucius group is represented by the Javanese snakehead (C. lucius), which is characterized by black spots on the head; The Micropeltes group is represented by the largest giant snakehead; The Striata group, on the other hand, includes the spotted snakehead and its related species, which are widely distributed in the wetlands of Southeast Asian plains (Britz et al., 2020). Molecular systematics supports the formation of several closely related monophyletic groups of these Southeast Asian blackfish species. The mitochondrial genome study by Sun et al. (2024) showed a close relationship between the yellow snakehead from Assam, India and the dwarf snakehead (C. burmanica) from Myanmar, both of which are close to the Jurassic snakehead group rather than the traditionally thought Yellow snakehead group.

3.3 Molecular clock estimation and spatiotemporal dispersion patterns of lineages

Researchers used a molecular clock method to estimate when each Channa lineage branched off. This helps link blackfish evolution with Earth’s climate and geological history. It also lets scientists guess how these fish spread over time and space (Britz et al., 2020). In Asia, most of the major blackfish lineages began forming between the late Oligocene and early Miocene, which is around 18 to 30 million years ago (Kumar et al., 2021). The evolution of snakehead fish is related to geological and climate changes. During the Miocene period, small snakehead fish were particularly active. Against the background of frequent land and sea alternation in Southeast Asia, they underwent significant adaptive evolution (Prazdnikov, 2023). As sea levels rose and fell, land bridges appeared and disappeared. This broke up the fish's habitats. Separate groups of fish then evolved differently in isolated mountain and island areas.

The climate oscillations of the Quaternary glacial interglacial cycle have also shaped the distribution pattern of existing species of moon snakehead. The genetic structure of the C. gachua population in the Indochinese Peninsula clearly reflects the water system isolation events caused by historical sea level changes (Wang et al., 2021). The species differentiation of the moon snakehead in the Indian subcontinent may have responded to regional geomorphological evolution, including the uplift process of the Deccan Plateau and the formation of the Ganges Brahmaputra River system (Böhme, 2004; Adamson et al., 2010). These geological activities create necessary isolation conditions for species differentiation by altering water system connectivity.

4 Adaptive Evolutionary Characteristics Revealed by Snakehead Genome Data

4.1 Genomic characteristics of representative Snakehead species

In the past few years, studies on snakehead fish genomes have helped scientists better understand how these fish evolved. Thanks to new sequencing tools, researchers have now completed the genome sequencing and assembly of several well-known snakehead species (Han et al., 2025; Htoo et al., 2015). The findings show that the genome size of snakehead fish is somewhere in the middle-not too big or too small. When comparing their DNA with that of other freshwater fish, both similarities and differences were found. For example, snakeheads have chromosome structures that are quite similar to goldfish and betta fish (Ou et al., 2021; Andrews et al., 2023). But in certain small parts of the genome, some key changes stand out. Gene families like olfactory receptors and heat shock proteins are much larger in snakeheads, showing that these areas have expanded more in their DNA (Huang et al., 2022).

4.2 Genes related to oxygen deficiency and hypoxia adaptation

One of the most acclaimed adaptive features of the blackfish genus is its tolerance to low oxygen environments and air breathing ability. This adaptability is also reflected at the genomic level. There is a correlation between the low oxygen tolerance of different fish species and their metabolic preferences: fish that tend to use fat as the main energy source for metabolism are less tolerant to hypoxia, while fish that prefer glycolysis have stronger hypoxia tolerance (Sudasinghe et al., 2020). The genomic basis for the adaptation of black fish to low oxygen can be summarized as: achieving efficient oxygen supply and low oxygen consumption through genetic modification of organ structure and metabolic physiology. On the one hand, it evolved auxiliary respiratory organs and strengthened them in angiogenesis and oxygen sensing molecular pathways (involving genes such as HIF/VEGF); On the other hand, adjusting metabolic patterns and oxygen carrier functions (involving Hb multi genes and metabolic enzyme genes) to maintain life activities during hypoxia. These imprints of adaptation on the genome include the expansion of related gene families, changes in regulatory sequences, and adaptive mutations at key protein sites (Rüber et al., 2020; Laskar et al., 2023).

4.3 Immune system and adaptation to environmental stress

Snakehead fish have a wide distribution, inhabiting environments ranging from clear streams to muddy rice paddies, and are exposed to a variety of pathogens and environmental stressors. This may have led to the evolution of unique adaptive traits in their immune system. Snakehead fish also perform well in acquired immunity. For example, studies have found that snakehead fish infection with snakehead herpes virus (SHVV), an invasive aquatic virus, induces a strong type I interferon response and expression of antiviral proteins (Cao et al., 2021). The adaptive evolution of the snakehead immune system is primarily manifested in: expanding the range of pathogen recognition and response through gene duplication and functional enhancement (expansion of innate immune receptors such as TLRs, and increased activity of the interferon pathway), and adapting to changing environments through changes in gene regulation (rhythmic regulation and stress induction of immune gene expression). This allows snakehead to thrive in pathogen-laden swamps and ponds without experiencing disease outbreaks, and also allows them to rapidly mobilize immunity and maintain homeostasis during sudden environmental changes (Cao et al., 2021; Ou et al., 2021).

4.4 Genetic changes in behavioral and niche adaptation

Blackfish show many differences in their behavior and ecological roles. Some are more aggressive about their territory. Others differ in how they reproduce or in their daily activity patterns. These differences seem to be linked to changes in their genes over time. The evolution of snakehead fish has formed a series of unique genetic characteristics, which have become important driving forces for its adaptation to the environment: for example, genes related to perception and behavioral regulation have undergone significant mutations, giving it advantages in foraging efficiency and intraspecific communication.

In the adaptation to exercise and survival, muscle and stress-related genes (such as FoxO pathway genes) also undergo adaptive changes. These changes enable snakehead fish to move on land and cope with harsh environmental conditions (Ou et al., 2021; Townley et al., 2022). Subsequent research can systematically analyze the genetic basis of ecological adaptation strategies of different black fish species by integrating comparative genomics and transcriptomics methods, combined with behavioral ecology experiments. Cross analysis of multiple omics data is expected to reveal the complex interactions between genotype phenotype environment.

5 Comparative and Convergent Case Studies of Adaptive Evolution

5.1 Comparative analysis with other air-breathing fishes

As a fish species capable of air respiration, the adaptation mechanism of the Blackfish genus to terrestrial respiration is similar to that of other fish species that have independently evolved respiratory organs (Jiang et al., 2016). Climbing sea bass (such as Anabas testudinius) and fighting fish, which have similar functions to black fish, also have auxiliary respiratory structures and can directly breathe air in hypoxic environments (Goodrich et al., 2020). Although these distant groups have different anatomical structures (climbing loaches are labyrinthine organs on their gills, while lungfish evolved from swim bladder to lungs, etc.), similar evolutionary characteristics often appear in molecular adaptation (Ou et al., 2021). For example, they all improve oxygen supply to auxiliary respiratory organs by enhancing the HIF-1 α signaling pathway and promoting angiogenesis pathway (Laskar et al., 2023).

At the genetic level, some gene modules with similar patterns or functions experience similar selection pressure in air breathing fish. For example, the mucin gene responsible for maintaining a moist environment during respiration is highly expressed in both the intestinal tract of loaches and the gill organs of black fish to avoid tissue dryness (Laskar et al., 2023). For example, neurotransmitter genes that regulate respiratory rhythms show positive selection signs in both lungfish and blackfish, indicating their importance in periodic respiratory behavior (Rüber et al., 2020).

5.2 Genomic adaptation differences among Snakehead ecotypes

Genomic adaptive differences exist among different snakehead ecotypes, but current research is only beginning to explore them. Genomic adaptations and divergence often occur between highland and lowland, and between river and swamp-dwelling snakeheads, specifically in response to their respective environments. Genomic resources for snakehead (C. argus) provide a foundation for studying adaptive mutations between different ecological types, such as highland and lowland, and aquatic and swamp-dwelling habitats (Xu et al., 2017). Research by Ou et al. (2021) revealed that snakehead fish (Canna argus) have a stronger response to low-temperature stress than snakehead fish (Canna maculatus): they rapidly activate cold shock proteins and metabolic regulatory genes during cooling, thus better adapting to cold waters. Scientists recently found Channa harcourt butleri fish in remote parts of eastern India (Prazdnikov, 2023). This discovery shows how being separated by geography helps create new fish species. Studies comparing chromosomes found big differences between Channa fish species. For example, C. gachua and C. stewartii have very different chromosome patterns (Figure 2). These differences probably show how each species adapted to their environment in unique ways.

Geographical differences significantly influence the evolutionary paths of Channa fish. Under prolonged isolation, populations gradually undergo adaptive changes to cope with diverse aquatic environments. Just as in captivity, targeted breeding can lead to faster growth rates and enhanced disease resistance in snakehead fish within a short period of time (Cao et al., 2021).

6 Integrated Analysis of Phylogeny and Functional Evolution

6.1 Integrating gene evolutionary trajectories with lineage divergence

By looking at how different snakehead fish groups evolved and how their genes changed, we can see how physical changes connect to genetic changes. For instance, early snakehead ancestors first developed simple gills for breathing. Later, different groups evolved their own special genes to control breathing (Cox and Logan, 2021; Laskar et al., 2023). This two-step process shows we need to study both genes and family trees to understand complex features.

6.2 Modeling with integrated omics and ecological data

New computer tools now let scientists study genes and environmental factors together (Stupp et al., 2021). These tools help create models that connect genes, environment, and physical traits (Ma et al., 2023). By comparing gene patterns with environmental factors like temperature and water quality, we can predict how species might adapt and see how they spread in the past. For example, studies of Southeast Asian snakeheads using ancient climate data and genes showed sea level changes shaped where these fish live (Prazdnikov, 2023).

A new area of research is studying how microbes-like those in water or in the fish’s gut-interact with fish genes. Changes in water quality may affect gut microbes, and these microbes can, in turn, affect how the fish uses energy or adapts. By using multi-omics tools, scientists can look at both the microbes and the fish’s genes at the same time to see how they work together.

7 Concluding Remarks

Channa spp., as a highly diverse group of freshwater fish, exhibit a diversity in morphology, ecology, and geographic distribution that is the result of long-term evolutionary adaptation. With the help of modern molecular systematics research, we have basically clarified the phylogenetic relationship of the genus Blackfish: the genus is divided into several major evolutionary branches, and the geographical distribution of each branch is closely related to geological historical events, such as the Himalayan uplift and sea level fluctuations shaping many regional endemic species. Phylogenetic reconstruction has also clarified long-standing taxonomic challenges, identified cryptic species, and corrected some misclassifications, providing a basis for accurate assessment of species diversity.

The genetic basis of behavioral ecological adaptability is also worthy of attention. The complex behaviors of seasonal dormancy, parental care for infants, and terrestrial migration are closely related to the evolution of neuroendocrine regulatory networks and metabolism related genes. It can be said that the genome of the blackfish genus encodes its "evolutionary blueprint" for conquering diverse habitats.

Future research can integrate multi-source genetic data to identify core genes that determine adaptability and construct high-quality genetic maps, thereby providing a foundation for understanding key traits. With the maturity of gene editing tools such as CRISPR, it will be possible to verify the functional genes closely related to hypoxic survival. At the same time, it is necessary to integrate these molecular mechanisms with observations of natural behavior and aquaculture practices to form a research system that emphasizes both theory and application.

Acknowledgments

We would like to thank our colleagues and research partners for their support and assistance in the literature compilation process.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

References

Adamson E., Hurwood D., and Mather P., 2010, A reappraisal of the evolution of Asian snakehead fishes (Pisces, Channidae) using molecular data from multiple genes and fossil calibration, Molecular Phylogenetics and Evolution, 56(2): 707-717.

https://doi.org/10.1016/j.ympev.2010.03.027

Andrews K.R., Seaborn T., Egan J.P., Fagnan M.W., New D.D., Chen Z., Hohenlohe P., Waits L., Caudill C., and Narum S.R., 2023, Whole genome resequencing identifies local adaptation associated with environmental variation for redband trout, Molecular Ecology, 32(4): 800-818.

https://doi.org/10.1111/mec.16810

Bhardwaj A.K., Chandra R.K., Pati A.K., and Tripathi M.K., 2022, Seasonal immune rhythm of leukocytes in the freshwater snakehead fish (Channa punctatus), Journal of Comparative Physiology B, 192(6): 727-736.

https://doi.org/10.1007/s00360-022-01460-7

Böhme M., 2004, Migration history of air-breathing fishes reveals Neogene atmospheric circulation patterns, Geology, 32: 393-396.

https://doi.org/10.1130/G20316.1

Britz R., Dahanukar N., Anoop V.K., Philip S., Clark B., Raghavan R., and Rüber L., 2020, Aenigmachannidae, a new family of snakehead fishes (Teleostei: Channoidei) from subterranean waters of South India, Scientific Reports, 10(1): 16081.

https://doi.org/10.1038/s41598-020-73129-6

Britz R., Hui T.H., and Rüber L., 2024, Four new species of Channa from Myanmar (Teleostei, Labyrinthici, Channidae), Raffles Bulletin of Zoology, 2024: 72.

Cao P., Sun W., Zhang Y., Zhou Z., Zhang X., and Liu X., 2021, Susceptibility and immune responses of hybrid snakehead (Channa maculata♀ × Channa argus♂) following infection with snakehead fish vesiculovirus, Aquaculture, 533: 736113.

https://doi.org/10.1016/j.aquaculture.2020.736113

Cox C., and Logan M., 2021, Using integrative biology to infer adaptation from comparisons of two (or a few) species, Physiological and Biochemical Zoology, 94: 162-170.

https://doi.org/10.1086/714018

Goodrich H., Bayley M., Birgersson L., Davison W., Johannsson O., Kim A., My P., Tinh T., Thanh P., Thanh H., and Wood C., 2020, Understanding the gastrointestinal physiology and responses to feeding in air-breathing Anabantiform fishes, Journal of Fish Biology, 96(4): 986-1003.

https://doi.org/10.1111/jfb.14288

Han X., Su X., Che M., Liu L., Nie P., and Wang S., 2025, Identification and expression analyses of IL-17/IL-17R gene family in snakehead (Channa argus) following Nocardia seriolae infection, Genes, 16(3): 253.

https://doi.org/10.3390/genes16030253

Htoo H., Laskar B.A., Lee S.R., Vu S.V., Phyo P.M.M., Thitsar P., Kim H., and Kundu S., 2025, Unified morphological and genetic analyses confirm the existence of the dwarf snakehead Channa shingon (Anabantiformes: Channidae) in Kachin State, Myanmar, Fishes, 10(3): 100.

https://doi.org/10.3390/fishes10030100

Huang S., Yang L., Zhang L., Sun B., Gao J., Chen Z., Zhong L., and Cao X., 2022, Endogenic upregulations of HIF/VEGF signaling pathway genes promote air-breathing organ angiogenesis in bimodal respiration fish, Functional and Integrative Genomics, 22(1): 65-76.

https://doi.org/10.1007/s10142-021-00822-8

Jiang Y., Feng S., Xu J., Zhang S., Li S., Sun X., and Xu P., 2016, Comparative transcriptome analysis between aquatic and aerial breathing organs of Channa argus to reveal the genetic basis underlying bimodal respiration, Marine Genomics, 29: 89-96.

https://doi.org/10.1016/j.margen.2016.06.002

Kumar R., Mohanty U.L., and Pillai B.R., 2021, Effect of hormonal stimulation on captive broodstock maturation, induced breeding and spawning performance of striped snakehead, Channa striata (Bloch, 1793), Animal Reproduction Science, 224: 106650.

https://doi.org/10.1016/j.anireprosci.2020.106650

Laskar B.A., Adimalla H., Kundu S., Jaiswal D., and Chandra K., 2023, Genetic evidence on the occurrence of Channa harcourtbutleri (Annandale, 1918) in Eastern Ghats, India: First report from mainland India, Journal of Threatened Taxa, 15(3): 22834-22840.

https://doi.org/10.11609/jott.6894.15.3.22834-22840

Ma Q., Luo Y., Zhong J., Limbu S.M., Li L.Y., Chen L.Q., Qiao F., Zhang M., Lin Q., and Du Z.Y., 2023, Hypoxia tolerance in fish depends on catabolic preference between lipids and carbohydrates, Zoological Research, 44(5): 954.

https://doi.org/10.24272/j.issn.2095-8137.2023.098

Ou M., Huang R., Yang C., Gui B., Luo Q., Zhao J., Li Y., Liao L., Zhu Z., Wang Y., and Chen K., 2021, Chromosome-level genome assemblies of Channa argus and Channa maculata and comparative analysis of their temperature adaptability, GigaScience, 10(10): giab070.

https://doi.org/10.1093/gigascience/giab070

Pamenter M.E., Hall J.E., Tanabe Y., and Simonson T.S., 2020, Cross-species insights into genomic adaptations to hypoxia, Frontiers in Genetics, 11: 743.

https://doi.org/10.3389/fgene.2020.00743

Praveenraj J., Thackeray T., Singh S.G., Uma A., Moulitharan N., and Mukhim B.K., 2020, A new species of snakehead (Teleostei: Channidae) from East Khasi Hills, Meghalaya, Northeastern India, Copeia, 108(4): 938-947.

https://doi.org/10.1643/CI2020007

Praveenraj J., Uma A., Moulitharan N., and Singh S.G., 2019, A new species of dwarf Channa (Teleostei: Channidae) from Meghalaya, northeast India, Copeia, 107(1): 61-70.

https://doi.org/10.1643/CI-18-079

Prazdnikov D.V., 2023, Chromosome complements of Channa lucius and C. striata from Phu Quoc Island and karyotypic evolution in snakehead fishes (Actinopterygii, Channidae), Comparative Cytogenetics, 17: 1.

https://doi.org/10.3897/compcytogen.v17.i1.94943

Rüber L., Tan H.H., and Britz R., 2020, Snakehead (Teleostei: Channidae) diversity and the Eastern Himalaya biodiversity hotspot, Journal of Zoological Systematics and Evolutionary Research, 58(1): 356-386.

https://doi.org/10.1111/jzs.12324

Stupp D., Sharon E., Bloch I., Zitnik M., Zuk O., and Tabach Y., 2021, Co-evolution-based machine learning for predicting functional interactions between human genes, Nature Communications, 12(1): 6454.

https://doi.org/10.1038/s41467-021-26792-w

Sudasinghe H., Pethiyagoda R., Meegaskumbura M., Maduwage K., and Britz R., 2020, Channa kelaartii, a valid species of dwarf snakehead from Sri Lanka and southern peninsular India (Teleostei: Channidae), Vertebrate Zoology, 70: 157-170.

Sun D., Wen H., Qi X., Li C., Wang L., Li J., Zhu M., Zhang X., and Li Y., 2024, Chromosome-level genome assembly of the northern snakehead (Channa argus) using PacBio and Hi-C technologies, Scientific Data, 11(1): 1437.

https://doi.org/10.1038/s41597-024-04314-9

Townley I.K., Babin C.H., Murphy T.E., Summa C.M., and Rees B.B., 2022, Genomic analysis of hypoxia inducible factor alpha in ray-finned fishes reveals missing ohnologs and evidence of widespread positive selection, Scientific Reports, 12(1): 22312.

https://doi.org/10.1038/s41598-022-26876-7

Wang J., Li C., Chen J., Wang J., Jin J., Jiang S., Yan L., Lin H., and Zhao J., 2021, Phylogeographic structure of the dwarf snakehead (Channa gachua) around Gulf of Tonkin: Historical biogeography and pronounced effects of sea-level changes, Ecology and Evolution, 11: 12583-12595.

https://doi.org/10.1002/ece3.8003

Xu J., Bian C., Chen K., Liu G., Jiang Y., Luo Q., You X., Peng W., Li J., and others, 2017, Draft genome of the northern snakehead, Channa argus, GigaScience, 6: 1-5.

https://doi.org/10.1093/gigascience/gix011

Zhang Y., Lu Y., Xu F., Zhang X., Wu Y., Zhao J., and Ou M., 2024, Molecular characterization, expression pattern, DNA methylation and gene disruption of figla in blotched snakehead (Channa maculata), Animals, 14(3): 491.

https://doi.org/10.3390/ani14030491

Zhou C., Li Y., Zhou Y., Zou Y., Yuan D., Deng X., and Li M., 2022, Chromosome-scale assembly and characterization of the albino northern snakehead, Channa argus var. (Teleostei: Channidae) genome, Frontiers in Marine Science, 9: 839225.

https://doi.org/10.3389/fmars.2022.839225