3. Results
3.1. Identification of the retrieved water mould
The hypothetical problem of this manuscript was built on the
emerging event of mass mortalities of angelfish eggs in the
investigated private ornamental fish farm at Giza, Egypt.
The overall assessment of the achieved data confirmed that
mortality rates among examined angelfish eggs have approached
70% of the entire egg stock. Reduced hatchability
among examined eggs was very noticeable. Whitish opaque
eggs (dead eggs) were abundant.
Ten water mould isolates were obtained from the infected
eggs. Visual inspection of the cultured SDA plates has exposed
the eminent growth of mould colonies. The colonies can be
morphologically depicted as cysts of whitish cottony long hairs
that quickly shifted to grey then black after 96 h. Microscopically,
fungal colonies were characterized by an extensive and
dense mycelium. By examination, 3 out of 10 isolates showed
the characteristic appearance of branched nonseptated hyphae
together with masses of mature and immature sporangia,
which is indicative for asexual reproduction. Such sporangia
were filled with large number of spherical sporangiospores,
which were separated from the basal somatic hyphae by asmall septum. However, the majority of the retrieved isolates
(7/10 isolates) showed identical morphological characteristics
of Saprolegnia’ sexual reproduction such as terminal oogonia
with centric oospores and antheridia (Fig. 1).