Nannostomus britskii, (from the Greek: nanos = small, and the Latin stomus = relating to the mouth; britskii = in honor of ichthyologist, Heraldo A. Britski),[1] commonly known as the spotstripe pencilfish, is a freshwater species of fish belonging to the family Lebiasinidae of characins.[2] They were first described in 1978 by Stanley H. Weitzman along with two other new species (Nannostomus limatus and Nannostomus nitidus), from a collection of specimens preserved in the São Paulo museum.[3] They have been recorded from only two localities, both in Brazil.[4] No live specimens had been seen, collected, or exported for the aquarium trade until very recently.