Chemotaxis is the biological phenomenon that organisms move to a more favorable location in an environment with a chemical attractant or repellent. This paper considers the performance of the internal controllers generating the chemotaxis. We first propose performance indeces to capture the chemotaxis. Based on them, the performance is evaluated for two controller models, which are of model organisms for the chemotaxis, Escherichia coli and Paramecia. It is disclosed that the coli-type controller achieves the chemotaxis fast but roughly, while the paramecium-type controller achieves it slow but precisely.