Blue danio with a 6.5 – 7.0 pH, a water hardness of 8 – 12 dGH, and a temperature range of 73 – 77 °F (23–25 °C). Blue danios are egg-scatterers that spawn over coarse gravel beds. They will typically spawn at the first light of day. The eggs will hatch in about 36 hours. The taxonomic name honors A.F.G. Kerr, who collected the first specimen on Ko Yao Yai in 1929. Blue danio The blue danio or Kerr's danio,Turquoise danio ("Danio kerri") is a tropical fish belonging to the genus "Danio" in family Cyprinidae. The blue danio is found on the
Danio margaritatus with a markedly blunt snout, measuring just 2–2.5 cm standard length. The body is about three times as long as it is high. In general shape, it resembles "Danio erythromicron" more than any other known species. This species shows some sexual dimorphism: males have a bright-blue background color (dull blue-green in females), and their fins are more brightly colored. The tail end of their bodies (the caudal peduncle) is also higher than in females. The body is sprinkled with small, pearly dots. The back is bronzy green, and the belly in females is yellowish-white. The gill covers are transparent, letting