This thesis showed how nutrient availability affects the growth dynamics of two Hydra-associated bacterial species, Flavobacterium and Pseudomonas , using autoclaved lake water (ALW) and Hydra medium (HM). The initial hypothesis, predicting higher growth in nutrient-rich ALW, was only partially supported. Flavobacterium showed slightly higher CFU counts in ALW, while Pseudomonas unexpectedly grew more in HM. However, neither result was statistically significant. These results suggest that factors beyond nutrient content, such as metabolic preferences or substrate specificity, may influence bacterial proliferation. The limited number of replicates likely reduced the study's statistical power, emphasizing the need for larger sample sizes in future experiments. Overall, the research shows that microbes can respond to their environment in complex ways, and careful planning is important when designing such experiments.