Assessing the impact of three fish drugs on tetrahymenosis in Fish using environmental DNA techniques

Tetrahymenosis has resulted in significant economic losses for the ornamental fish farming industry in Harbin. While previous studies have investigated the outbreaks and histopathology of Tetrahymena pyriformis in fish, there is still a lack of study on the use of the application of fish drugs for prevention and treatment. This experiment aims to evaluate the efficacy of three fish drugs (copper, Nitrofural, Methylene Blue) in combating tetrahymenosis in goldfish. We utilized eDNA-based 16 s rDNA gene amplifiers sequencing and qPCR technologies to extract environmental samples and conducted high-throughput sequencing to assess the interaction between the diversity of T. pyriformis and other microorganisms in aquaculture water following the introduction of various fish medications. Our findings revealed that among the three fish drugs test, Nitrofural displayed the most promising effects, followed by Methylene Blue, while copper sulfate proved to be the least effective. Consequently, our study provides a treatment plan for addressing tetrahymenosis in goldfish and offers insights into the pathological changes in goldfish tissues following the onset of the disease.