Incidence of fungal infection of freshwater ornamental fish in Pakistan

An investigation was conducted on fungal diseases of three imported freshwater ornamental fish Carassius auratus (L.), Xiphophorus maculates (Günter) and Poecilia reticulate (Peters). A total of 45 fish specimens, were dissected. Different body parts of fish were infected and showed clinical signs. Clinical picture of C. auratus showed that scales were eroded and haemorrhage and lesions were on abdomen. Dorsal & caudal fin were disintegrated. In X. maculatus eyes and mouth was covered with fungal hyphae. The clinical picture of P. reticulata showed that gills were whitish due to the presence of fungal hyphae and caudal fin also had cotton wool like margin. The fungi isolated from the infected areas on the fish were cultured on different media, Malt extract agar (MEA), Sabouraud dextrose agar (SDA) and Potato dextrose agar (PDA). The fungus was allowed to grow for 5-7 days at 28-30 degree C. White, grey, black, brown, green and orange colors of colonies were observed. The slides were prepared and stained with 0.05% Trypanblue in lactophenol. The fungal infection in C. auratus, X. maculatus, and P. reticulatawere (80%), (80%) and (70%), respectively. Five genera of fungi were identified. Species of Aspergillus, Rhizopus, Mucor, Penicillium and Alternaria were isolated from C. auratus. Species of Aspergillus, Rhizopus, Mucor and Alternaria were isolated from X. maculatus. Species of Aspergillus, Mucor and Rhizopus were isolated from P. reticulata. Incidence of Aspergillus spp. was (47%), Rhizopus spp. (23.3%), Mucor spp. (10.3%), Penicillium spp. (8%) and Alternaria sp. (1.3%). Incidence of Aspergillus spp. was highest in the infected fish sample. Posterior part of the fishes had significantly higher (X2= 0.4, P=0.02) infection as compared to anterior part of the fishes. This study showed that fungi isolated from different freshwater ornamental fishes are considered as normal mycoflora but they can cause infection.