It turned out to be a snakehead (Channa argus), an invasive freshwater fish species in the family Channidae that surprised not only fishing enthusiasts but also scientists. According to IFLScience ...
Journal of Morphology, DOI - 10.1002/jmor.10243. Courtenay WR, Williams JD, BRITZ R, Yamamoto MN, Loiselle PV (2004) Identity of introduced snakeheads (Pisces, Channidae) in Hawaii and Madagascar, ...