Comparison of the sensitivity of Danio rerio and Poecilia reticulata to silver nitrate in short-term tests

The aim of this study is to assess the acute toxicity of silver nitrate in adult zebra fish and adult guppies and to compare the sensitivity of these species to this compound. Silver is a naturally occurring element in our environment and it combines with other elements such as sulfide, chloride, and nitrate. Silver, in the form of silver nitrate, is one of the most toxic metals affecting freshwater fish. Industry, particularly photographical and electrotechnical, is the major contributor of silver that is released into the environment. Tests of acute toxicity were performed on the most common species of aquarium fish, Danio rerio and Poecilia reticulata. Both zebra fish and guppies were exposed to progressive concentrations of silver nitrate; a semi-static method according to OECD 203 was used. In each test series, 6 tests of acute toxicity were conducted, with 10 fish used for each separate concentration and for the control group. The results (number of fish deaths in the individual test concentrations) were subjected to probit analysis (EKO-TOX 5.1 software) to determine the 96hLC₅₀ AgNO₃ values. The 96hLC₅₀ AgNO₃ value for the zebra fish was (mean ± SEM) 15 ± 0.52 μg/l and for the guppies was (mean ± SEM) 17.14 ± 5.43 μg/l. We didn't find any statistically significant difference between the sensitivity of zebra fish and guppies. The results reported in this study are in agreement with LC₅₀ values published in peer-reviewed literature, and conclude that AgNO₃ is one of the most toxic compounds known to fishery.