Atlassian's Crowd identity management system can be integrated with FishEye. Please see the document Integrating Crowd with FishEye in the Crowd Administrator's Guide.
Note:

• In FishEye versions 1.4 and later, support for Crowd is built in and configuration is greatly simplified.
• In FishEye versions 1.3.x and earlier, using Crowd required installing a custom authentication plugin on your FishEye server. In version 1.4, the custom authentication plugin is no longer required or supported.