Research Software has become a key asset to support the results described in academic publications, enabling effective data analysis and reproducibility. In order to ensure adherence of Research Software to the Findable, Accessible, Interoperable, and Reusable (FAIR) principles, the scientific community has proposed metadata guidelines and best practices. However, it is unclear how have these practices been adopted so far. This paper examines how different scientific communities describe Research Software with metadata to support FAIR, how do they adopt existing good practices regarding citation, documentation or versioning, and what is the current adoption of archival services for long term preservation. We carry out our analysis in the software registries of five science clusters (in domains ranging from Physics to Environmental Sciences), together with a multi-domain collaborative software registry. Our results highlight the main gaps in metadata adoption in the different communities, opening an opportunity for future contributions to aid researchers in adopting good FAIR and Open Science practices.