Nanosphromenus Gemma

Nanosphromenus Gemma

Nanosphromenus gemma (commonly known as the Jewel Gourami or Microsphromenus sp. "Vietnam") is a newly described species and genus of miniature labyrinth fish in the family Osphronemidae, officially published in July 2026 by Ralf Britz, Heok Hui Tan, and Lukas Rüber.

Key Characteristics & Taxonomy

• Scientific Classification: Family Osphronemidae (suborder Anabantoidei), representing a distinct new genus (Nanosphromenus).

• Phylogeny: Molecular analysis places Nanosphromenus as the sister group to Trichopsis (croaking gouramis).

• Size: Grows to a maximum standard length (SL) of about 15 mm to 18.7 mm, making it one of the smallest known anabantoids in the world.

• Fin Counts & Traits: Possesses a unique dorsal-fin ray count (XIX–XXI + 2–3) and anal-fin ray count (XX–XXIV + 4–5), along with specialized skeletal features like an exoccipital Baudelot's ligament insertion and a reduced cranial lateral-line system.

• Coloration & Etymology: Named gemma (Latin for "jewel") because sexually mature males display a striking bright red stripe, deep dark body pigmentation, and vivid iridescent scales. Females lack the bright red stripe in the upper dorsal half.

• Behavior: Male bubble-nest guardian reproduction, well-suited for peaceful planted aquariums.

• Distribution: Originally reported from an undisclosed area near Huế in Central Vietnam.