Annual killifishes are emerging eco-evolutionary developmental models due to their unique embryonic dormancy used to study development, metabolism, aging, and stress tolerance in vertebrates. They inhabit seasonal pools that desiccate, resulting in the death of the adult population. Unique adaptations including specialized egg structures and up to three diapauses that slow developmental and metabolic rates enable the embryonic population to survive dry seasons in the soil. When the habitat floods, annual killifish terminate their third diapause (DIII), hatch, and begin a new lifecycle. We sequenced the genome of the bi-annual Rio pearlfish, Nematolebias whitei. Rio pearlfish are native to seasonal pools in the coastal plains near Rio de Janeiro, Brazil, where they complete two life cycles per year. During DIII, pearlfish have fully developed, functioning organ systems when making changes to metabolism and cell cycle during developmental arrest. Our model species represents an independent origin of seasonality, different from other killifish species. DIII is tightly linked with expression of a complex family of hatching enzymes, and our analysis of these enzymes, including those of pearlfish, reveals a complex evolutionary history of hatching enzymes in killifishes. Additionally, we use the pearlfish to develop Killi-Kits as an educational outreach tool. Killi-Kits include dormant killifish eggs, a small tank, food, a clip-on smartphone microscope, and instructional online resources. A-FISH-ionados of all ages can observe killifish development with the smartphone microscope. Overall, we establish the Rio pearlfish as a novel research organism and educational toolkit for Extremo-Evo-Devo.