Are anonymous users counted towards Fisheye's license limits?
The short answer is no. If you are using Fisheye in your organization but most users require only anonymous access (that is, you have not set access restrictions on the content in your repositories), then an unlimited number of anonymous users can be accomodated regardless of the Fisheye license you are using.
Users accessing Fisheye anonymously are, for all intents and purposes, unlimited users.
However, if your users require permissions and controlled access to specific content in your repositories, then they will need to log in to Fisheye. Hence, these users will need to create accounts and will be factored into the license limit.