The Diamond Head Rummy Nose Tetra (Hemigrammus bleheri), also known as the Diamond Head Tetra, is a striking freshwater fish known for its shimmering "diamond" patch on the top of its head and its vivid red nose. Native to the Amazon River basin, this species is peaceful and best kept in schools, where their synchronized swimming adds a dynamic display to any well-planted aquarium. Their contrast of bright colors and active nature make them a favorite among aquarists.