Danio flagrans is very similar to the glowlight danio, D. choprae. © Rupert Collins

The Danio species referred to in the hobby as D. cf. choprae or ‘northern glowlight danio’ is officially described, and the original ‘glowlight danio’ D. choprae redescribed, in the latest volume of the journal ‘Ichthyological Exploration of Freshwaters’.

The former has also been referred to as D. sp. ‘Putao’ or D. ‘putaoensis’ in the aquarium trade but has now been named D. flagrans by Dr. Sven O. Kullander, the name taken from the Latin flagrans meaning flaming, blazing, burning, or glowing.

The two species share similar lifestyles and colour pattern but differ in certain aspects of morphology, with D. flagrans diagnosable by the following characters: body more slender (22.5-26.6 % SL vs. 26.6-31.6% SL in D. choprae); caudal peduncle longer (20.5-24.7 % SL vs. 16.1-19.1 % SL); base of anal-fin shorter (14.2-18.3 % SL vs. 19.2- 23.9 % SL); rostral barbels longer (10.3-18.7 % SL vs. 5.9-10.1 % SL), reaching beyond the preopercular margin in adults (vs. not reaching posterior margin of orbit); maxillary barbels longer, reaching to below base of pectoral-fin base (vs. not reaching base of pectoral-fin); lateral line almost always present, with up to seven perforated scales (vs. almost always absent, occasionally up to three perforated scales); more vertebrae contained in caudal peduncle (9-10 vs. 6-8); 9½-11½ branched anal-fin rays vs. 12½-13½, rarely 11½; base of anal-fin  hyaline (vs. base of anal-fin dark); no black streak in lower lobe of caudal-fin  (vs. usually present).

D. choprae is now an established aquarium favourite. © Peter Macguire

The new species is known only from a handful of streams in the upper Mali Hka river drainage, near Putao in northern Myanmar, this forming part of the much larger Ayeyarwaddy drainage.

For further information please refer to the full, open access paper: Kullander, S. O. 2012. Description of Danio flagrans, and redescription of D. choprae, two closely related species from the Ayeyarwaddy River drainage in northern Myanmar (Teleostei: Cyprinidae). Ichthyological Exploration of Freshwaters 23(3): 245-262.