The request names VirtualFish, which is not among the candidate products, so no source describes it directly. The closest matches are tools for managing Python virtual environments and fish shell itself; PyPA's virtualenv documentation covers isolated Python environments 6, and fish shell is the shell VirtualFish plugs into 4.

A question back: Do you want a tool that manages Python virtualenvs from fish (like VirtualFish), or are you looking for something else?

1. 1

   Virtualenv (PyPA documentation)pypa.ioverified and signed

   Documents the PyPA-maintained tooling for creating isolated Python virtual environments, the core job VirtualFish automates from the fish shell.

   WebsiteDocs

   for agents: virtual · environments · isolated

2. 2

   fish shellfishshell.comwebsite read, tools not yet checked

   A user-friendly command line shell for Linux and macOS with tab completion, scripting and abbreviations, the shell in which VirtualFish runs.

   WebsiteDocs

3. 3

   Pexpex-tool.orgverified and signed

   Packages Python programs into executables and works with virtualenv-style environments.

   Website

   for agents: virtualenv · package · executable

4. 4

   direnvdirenv.netwebsite read, tools not yet checked

   Loads and unloads environment variables per directory from a .envrc file, supporting fish, for project-specific environments.

   WebsiteDocs

   +2 community tools built for it