Study of ethanolic extract of green tea (Camellia sinensis) on the treatment of white spot disease in goldfish (Carassius auratus)

Ichthyophthirius multifilii (Ich) is likely to cause more damage to freshwater aquarium fish than other eukaryotic pathogens. Due to the reported side effects and environmental effects, scientists are trying to replace chemicals with plant extracts to treat this parasite. In this study, the effect of ethanolic extract of green tea (Camellia sinensis) in the treatment of fish infected with the Ich parasite was investigated. In this study, the effect of different dilutions (0.25, 0.2, 0.15, and 0.125 gr / l) of ethanolic extract of green tea on the average number of white spots on the body of each fish and also the average number of microscopic parasites per fish before, 24 hours later and also 7 days after exposure of infected fish to the extract was studied. After 7 days of treatment, the average number of white spots on the body per fish and the average number of parasites counted in 5 microscopic fields per fish, were not significantly different in 0.2, 0.15, and 0.125 gr/l groups. Among the three treatments, the lowest percentage of mortality during 7 days was related to the concentration of 0.125 gr/l (25 percent). Also, all fish died at 0.25 gr/l and the negative control groups. The results revealed that 75 percent of infected fish survived during treatment with 0.125 gr/L of green tea ethanolic extract, and the efficacy of the mentioned concentration for removal of parasites from fins and skin was near 100 percent. Therefore, it can be concluded that this concentration can be used with caution for the treatment of fish infected with Ichthyophthirius multifiliis