Abstract Mass mortalities of angelfish eggs accompanied with very low hatchability were reported
in a private ornamental fish farm in Egypt. Examined eggs were badly damaged by water mould
that was decisively confirmed as Saprolegnia species. Presumptive identification of the ten retrieved
isolates was initially suggestive of Saprolegnia species. Mycological investigations have revealed that
only 7 out of 10 isolates were capable of producing sexual stages. Therefore, using molecular tools
such as PCR coupled with partial sequencing of inter-transcribed spacer (ITS) gene was one of the
most important approaches to distinguish Saprolegnia parasitica from other water moulds. The
sequences of ITS gene data derived from eight isolates showed 100% similarity with S. parasitica
ATCC90312 sequence and the remaining two isolates were different in one nucleotide (99.9%).
The phylogenetic analysis of ITS genes grouped the ten isolates with other S. parasitica in one clad.
Further, to control such fungal infection, the efficacy of povidone iodine as surface disinfectant for
angelfish and their fertilized eggs were tested. By trial, it was obvious that the obtained post-rinsing
results were highly suggestive for the efficacy of povidone iodine as an efficient antifungal disinfectant
for both fish and eggs.
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