All cystoviruses are distinguished by their three strands (analogous to chromosomes) of dsRNA, totalling ~14 kb in length and their protein and lipid outer layer. No other bacteriophage have any lipid in their outer coat, though the Tectiviridae and the Corticoviridae have lipids within their capsids.
Most identified cystoviruses infect Pseudomonas species, but this is likely biased due to the method of screening and enrichment . The type species is Pseudomonas phage Φ6, but there are many other members of this family. Φ7, Φ8, Φ9, Φ10, Φ11, Φ12 and Φ13 have been identified and named , but other cystoviruses have also been isolated .
Members of the Cystoviridae appear to be most closely related to the Reoviridae , but also share homology with the Totiviridae. Cystoviruses are the only bacteriophage that are more closely related to viruses of eukaryotes than to other phage.