I examined the samples from two oxbow lakes (Cibakháza and Gyüre) of the Tisza. I also studied the formation of these wetlands and their habitat. I have mentioned the importance of Cladocera and oxbow lakes to reconstruct the past environmental changes. My objective was to compare the results of these samples with each other and with the previously conducted research to understand the relationship between fish and Cladocera communities. It includes a comprehensive explanation of the sampling sites, sampling procedure, as well as storage and processing of the samples.