Description of the ontogenic and larval period of discus fish (Symphysodon aequifasciatus)

Abstract

The aim of this study was to describe the embryonic and larval development of discus fish (Symphysodon aequifasciatus), and to determine the time required, hours post fertilization (hpf), for the emergence of various structures. To describe embryonic and larval stages, observations were made at regular periods under an optical microscope and images were taken with a digital camera attached to a microscope. The average temperature reached in the experimental tank was 27.9°C. Important facts in embryonic and larval development are described, such as the closure of the blastopore, which occurred at 31.5 hpf; a period of eruption, which occurred at 58.5 hpf; and a mouth opening, which occurred at 90.5 hpf; and larvae that exhibited oriented swimming and eating exogenous food at 136.5 hpf.

Effect of temperature during embryonic development and first feeding of Trichogaster leeri larvae

“…The differentiation of head and tail in embryonic development, and the appearance of the optic primordium and the somites had lower hpf values at all temperatures when compared with results obtained by Marimuthu & Haniffa (2007), Radael (2009) and Mattos et al (2015). This difference is probably related to the characteristics of the studied species and larval development level at the time of hatching.…”

“…Embryonic development time in this study showed a difference in function at the experimental temperatures used in all treatments. In general, the time to occurrence to events was faster than that observed in other tropical fish (Ferreira, 2007; Radael et al 2013; Mattos et al 2015).…”

“…This behaviour can be observed in this present study, as well as observed in kinguios 'var. comet', by Mahmud et al (2011), in Carassius auratus by Tsai et al (2013) and in discus fish, described by Mattos et al (2015).…”

“…In this study, the T. leeri larvae after hatching developed a large area of pigmentation in the yolk and in the embryonic axis, had a large reserve of yolk and exhibited little movement. The T. leeri larvae showed little morphological development at hatching, low swimming motility and little yolk reserve, besides having incomplete digestive tract morphology at the first feeding that may impair the development of animals during and after hatching (Portella, 2004; Mattos et al 2015). Until the digestive tract is fully developed, the animal is still dependent on endogenous feed.…”

Maternal mRNA input of growth and stress-response-related genes in cichlids in relation to egg size and trophic specialization

“…around 12 hpf in two African cichlids, Oreochromis niloticus and Astatotilapia burtoni [ 82 , 100 ], and 4 hpf in two American cichlids, Symphysodon aequifasciatus and Amphilophus spp. [ 83 , 101 ]. Therefore, we set out to investigate the maternal mRNA investment in cichlid eggs almost immediately after fertilization (up to 3 hpf) to minimize the effects of RNA degradation during early development.…”