Stiphodon elegans, commonly known as the Green Riffle Goby, is a species of freshwater goby. They can live from 3–8 years, but they still remain small throughout their lifespans, only growing to up to 5cm. Their physical appearance is described as small and elongated, with raised, slightly dorsal-set eyes, a pelvic sucker, which is a suction-like fin derived from a fused set of pelvic fins, and a subterminal mouth. Within their mouths, they have many rows of long, thin, sharp, densely packed polyphyodont teeth. They also have modified, hook-like structures on their pharyngeal jaw. The purpose behind this characteristic is not entirely clear, but is possibly correlated with their feeding behavior in their rocky habitats. This species exhibits sexual dimorphism, with males displaying vivid, spotted patterns across their bodies, and longer, more sharper angled fins, while females are covered in wide, horizontal black and cream-colored stripes and have shorter, more rounded fins. Males also change color depending on their breeding status. Males who are not breeding are a grayish, dull green, while actively breeding males turn a dark, almost black color with vibrant green stripes and dots across its entire body, particularly along their lateral line area. Unfortunately, most females in the Stiphodon genus look almost the exact same, making it difficult to identify the species when only females are present. Many different species of Stiphodon have been easily confused with one another, as most were placed under the initial classification of Stiphodon elegans after their discovery. Since the Green Riffle Goby’s first introduction to scientific journals in 1879, the taxonomy of the genus has been updated frequently over the years, particularly in the 1990’s and early 2000’s. This research led to many discoveries of separate, endemic species across the Pacific Ocean, most of which found that many populations of Stiphodon lived nearby one another, but would not interbreed. Trying to classify between each species has proven difficult, as identification characteristics have been mainly based on subtle differences in body measurements and coloration.

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