Blue Emperor Tetra

About

The blue emperor tetra (Inpaichthys kerri) is a small but richly colored South American fish from the upper Madeira River basin in Mato Grosso, Brazil, where it inhabits the waters of the Aripuanã River system. Males carry a deep iridescent blue-violet band along the lateral line that intensifies noticeably when rivals are present, while females tend toward a more muted, brownish tone. One reliable way to tell this species apart from the superficially similar emperor tetra is the presence of an adipose fin, which Inpaichthys has and Nematobrycon does not. It is also the only species in its genus, which gives it a somewhat unique taxonomic standing. In the aquarium, this is a peaceful, active fish that belongs in a group of at least six. Keeping numbers up is genuinely important here. The mild fin-nipping reputation the species has collected over the years mostly disappears when it is given enough company, and any squabbling stays between males rather than being directed at tankmates. It fits well alongside other small South American species: companion tetras, pencilfish, Corydoras, Apistogramma, and Otocinclus are all sensible choices. Breeding is achievable for patient intermediate keepers willing to set up a dedicated spawning tank with soft, acidic water and fine-leaved cover. The fry are small and require infusoria in their earliest days.