Efficacy of acriflavin chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection in Pterophyllum scalare

Abstract

The article describes cases of saprolegniosis in Pterophyllum scalare in private aquaristics and assesses the therapeutic efficacy of acriflafin chloride against Saprolegnia parasitica infection. To establish the diagnosis, the clinical signs present in sick fish, the results of mycological and microscopic examinations are taken into account. Some chemical and mycological indices of aquarium water have been studied, and also mycological studies of fish feed have been carried out. It is established that the disease of fish develops against the background of adverse changes in physical, chemical composition and microbiocenosis of aquarium water. Low water temperature, high levels of phosphates and pH, a significant level of organic pollution, compared to the norm, provoke the accumulation of opportunistic microbiota, resulting in imbalance in the parasite-host system and the development of clinical manifestations of saprolegniosis in fish. It was found that 44.4% of the studied feed samples fed to fish were contaminated with epiphytic micromycetes. Micromycetes are represented by the genera Aspergillus, Penicilium, Fusarium, Mucor, Rhizopus. Among the studied feeds, the most affected by fungi were larvae of Chironomus plumosus and dry Daphnia pulex. According to the results of our studies during outbreaks of saprolegniosis, the pH of aquarium water was 8.1 ± 0.7, the content of phosphates – 5.6 ± 1.1 mg/L, micromycetes – 18.0 ± 1.2 CFU/100 cm3. Aspergillus flavus, A. niger and Penicillium canescens were detected in the studied water samples. With saprolegniosis, the angelfish have a reduced appetite, spots, ulcers, white thin threads, and a cotton-like plaque appear on certain areas of the skin, fins, eyes, and gills. It is established that effective means for the treatment of sick fish are external use in the form of a long bath of acriflavine chloride and extract of Melaleuca alternifolia. It is also effective to increase the water temperature to 25–27 °С, to ensure the normative fish-holding density in aquariums and to exclude from the diet fish feed contaminated with micromycetes. After using the drugs for two weeks every other day, water was replaced by 20% of the aquarium volume and aerated. As a result of the treatment, gradual healing of skin lesions and recovery of 65% of fish with signs of lesions of the outer coverings were registered. Thus, the article analyzes the causes of saprolegniosis in angelfish common in private aquariums, describes the clinical signs of the disease and assesses the therapeutic efficacy of acriflavine chloride and Melaleuca alternifolia extract against Saprolegnia parasitica infection. Prospects for further research lie in search of more effective and environmentally friendly means for the treatment of saprolegniosis in aquarium fish.