2fluorescence in situ hybridization (fish) is useful in microbial ecology, allows identification of particular bacterial groups in mixed samples and uses virus hosts. uses a labeled probe, is useful in microbial ecology, and allows identification of particular bacterial groups in mixed samples. uses virus hosts, uses a labeled probe, and is useful in microbial ecology. is useful in microbial ecology, allows identification of particular bacterial groups in mixed samples and depends on electron microscopy. uses a labeled probe, allows identification of particular bacterial groups in mixed samples, and uses virus hosts.