Developmental morphology and growth patterns of laboratory-reared giraffe cichlid, Nimbochromis venustus Boulenger, 1908

Abstract

The giraffe cichlid Nimbochromis venustus Boulenger, 1908 is a well-known species in aquarium trade. The laboratory-reared electric giraffe cichlid was studied in terms of early morphological development and allometric growth pattern from hatching until the juvenile stage i.e.51 dph. Total length increased linearly from hatching until 51 dph, with a high regression coefficient. The yolk sac exhaustion completed throughout 15 days. Significant morphological and morphometric variations occurred before the yolk sac absorption and early juvenile stage by evolving the anterior and posterior body section which improve swimming ability and food capturing. Positive growth coefficient of the body and trunk lengths were occurred after inflexion point coinciding with development of digestive system function. Eye diameter showed negative allometry at the inflexion point of 9.3 mm, continuing with positive growth rate until day 51. Body shape variation in early life history revealed consequent development in anterior and posterior body section in preflexion phase and development of body and trunk length in post flexion phase to support high survival of larvae. The present study emphasizes ontogenic study of different species to interpret biology and ecology of fish in association with evolutionary biology.