The gwyniad (Coregonus pennantii) is a freshwater whitefish native to Bala Lake (Llyn Tegid) in northern Wales. The population is threatened by deteriorating water quality and by the ruffe, a fish introduced to the lake in the 1980s and now eating the eggs and fry of gwyniad. As a conservation measure, eggs of gwyniad were transferred to Llyn Arenig Fawr, a nearby lake, between 2003 and 2007.