Kerry Blue Emperor Tetra (Inpaichthys kerri)

Usually sold as the blue emperor tetra, this is its own species — Inpaichthys kerri, a smaller cousin of the true emperor — with the emperor’s purple-gold sheen deepened into a saturated, full-body blue. The trade name is a mangling of kerri, not a terrier reference. Males carry the color; females run gold-brown. Otherwise it keeps everything people like about the emperor: deep-bodied, calm, and a genuine schooler rather than a loner. The blue reads strongest under decent lighting in a tight group.

Care level: Easy · Temperament: Peaceful, shoaling · Max size: ~1.6" · Min tank: 20 gal · Diet: Omnivore, flake/micro-pellet