Determination of factors that affect breeding in discus (Symphysodon spp.) and developmental characteristics of larvae/juveniles

In this study, factors that effect breeding and larval rearing of the commercially important tropical aquarium fish discus (S.spp) have been studied and histomorphological development of larvae and juveniles has been described. For his purpose, initially, the effects of water quality parameters such as temperature, pH, conductivity and hardness as well as environmental parameters such as photoperiod on the periodicity of spawning, fecundity and larval survival have been investigated. The hatching rates of eggs and survival of larvae were compared for eggs and larvae that either received parental care or hatched and cultured artificially. The survival rates of larvae and juveniles reared at different water hardness were determined. The effects of 3 different feeding protocols on the survival of larvae during first feeding with rotifers and Artemia were compared for larvae that received either parental care or reared artificially. The morphological development of larvae from hatching to 32 days after hatch (DAH) were described using photographical and histological techniques. As a result, crucial factors that affects breeding of adults and survival of larval/early juvenile stages were described.