SPTB and hypochromic anemia: As anemic mutants such as riesling (also known as sptb) (Liao et al., 2000), merlot/chablis (also known as epb41b) (Shafizadeh et al., 2002) or retsina (also known as slc4a1a) (Paw et al., 2003) develop cardiomegaly as a result of cardiac compensation for oxygen transport, we sought to define whether hypochromic anemia in eng−/− fish could account for hypoxia detected by 15 dpf.