Studies on Relationship Between Bacterial and Fungal Infections in Some Freshwater Fish

Abstract

This study aimed to, spotlight on, isolation and identification of the most common Bacterial and systemic Mycotic agent from cultured Oreochromis niloticus, study the incidence, prevalence and organs distributions of the isolated Bacteria and Fungi among the examined diseased fish, investigated the effect of different water quality parameters on the incidence such etiological agents and relationship studies between Bacterial and Mycotic diseases in examined fish. A total number of 100 diseased O. niloticus that, weighed 80 ±mg and 18 ± 0.2 cm in length were randomly collected from earthen ponds in Alexandria private cultured freshwater farms in January 2021. A bacteriological analysis of naturally 400 samples isolated from 100 infected fishes confirmed 400 positive samples and mycological analysis of 400 samples confirmed 214 positive samples. Morphologically, isolated bacteria were Gram –ve represented by Pseudomonas fluorescence, Schwenellea spp, Pseudomonas putediae, Pseudomonas aeruoginosa and Gram +ve bacteria represented by Streptococcus agalactia. Fungal isolates are represented by Aspergillus niger, Asp. flavus, Asp. fumigatus, Asp. parasiticus, Geotrichum spp., Candida spp. and Torulopsis spp. Combination between bacteria and fungi in fish ponds agreviates the morbidity and mortality rates.