Blueberry galaxies (BGs) are fainter, less massive, and lower redshift counterparts of the GPs. ^[1] They are generally very small dwarf starburst galaxies that have very high ionisation rates and also have some of the lowest stellar masses and metallicities of starburst galaxies, ^[2] though a 'massive' BG has been studied. ^[3] Two BGs have and are among the most metal-poor galaxies known, while the larger sample exist in low-density environments, similar to GPs. ^[2] BGs are more compact than GPs being less than 1/3000 the size of the Milky Way. ^[4] BGs form one of the youngest classes of star-forming galaxies with median ages ≤70 Myr. ^[5]

While Huan (2017) identified a sample of 40 BGs, a much larger sample was acquired using data from the LAMOST DR9 survey. ^[6] Siqi Liu and fellow authors found 270 Blueberries, as well as GPs and 'Purple Grapes'. ^[7] The observations found 1,417 new compact galaxies, nearly twice as many as formerly known. ^[7] Chinese researchers undertook a systematic study of the star formation rates, metallicities and environments of the compact galaxies that have different colours because of the different positions of emission lines in the photometric bands. ^[8] They were named Blueberries just after GPs had been discovered in December 2007. In 2011, Izotov and fellow authors wrote that GPs, Blueberries and Purple Grapes were Luminous Compact Galaxies at different distances. ^[9]