We found that medaka has two subtypes of blue (SWS2-A and SWS2-B), two
subtypes of red (LWS-A and LWS-B) and three subtypes of green (RH2-A, RH2-B,
and RH2-C) opsin genes in the genome. We also found that the two blue opsins
and the three green opsins genes are spectrally differentiated.