The Guianas
Nannostomus harrisoni, (from the Greek: "nanos" = small, and the Latin "stomus" = relating to the mouth; "harrisoni" = in honor of geologist, John Burchmore Harrison), is a species of pencil fish. Native to The Guianas, the species displays a single horizontal stripe of intense black, and blood red adornments on its fins. "N. harrisoni" is often confused with "Nannostomus unifasciatus", another long, slender, single-striped species with similar profile and coloration, but "N. harrisoni" swims in a horizontal posture, as opposed to the snout-up oblique posture of "N.unifasciatus", and the bright red adornments on the ventral fins of "N. harrisoni" are absent in "N. unifasciatus". Though the recently described species "N. grandis" has been dubbed the largest member of the genus, adults of "N. harrisoni" commonly grow to a length of 70 mm, making it in fact the largest species of pencil fish described to date. It is commonly known as Harrison's pencilfish.