Wikipedia
Sceleropages is a genus of freshwater fishes found in Asia and Australia. Four species are currently recognized. All are carnivorous and have great jumping ability. Most are endangered in the wild to some degree. Scleropages species are highly valued as aquarium fish, particularly by those from Asian cultures.
Before 2003, three species were recognized from this genus (S. formosus, S. jardinii, and S. leichardti). A fourth species, S. inscriptus, was described from Myanmar in 2012. In 2003, a study redescribed several naturally occurring color varieties of S. formosus, the Asian arowana, into four separate species. The majority of researchers dispute these redescriptions, arguing that the published data are insufficient to justify recognizing more than one Southeast Asian species of Scleropages, and that divergent haplotypes used to distinguish the color strains into isolated species were found within a single color strain, contradicting the findings. They are considered monotypic, consisting of closely related haplotypes based on color.
The ancestor of the Australian arowanas, S. jardinii and S. leichardti, diverged from the ancestor of the Asian arowanas about 140 million years ago, during the Early Cretaceous period. The morphological similarity of all six species shows that little evolutionary change has taken place recently for these ancient fish. The genus had a much wider distribution during the early Cenozoic, with fossil remains known from the Paleocene of Niger and Belgium.