Lythrypnus dalli, the Blue-banded goby, is a species of goby native to the eastern Pacific from Monterey Bay (California) to northern Peru, including the Gulf of California. It can be found in coastal waters at depths of from 0 to 76 metres (0 to 249 ft) with rocky substrates in which there are crevices for concealment. It is also known to hide amongst the spines of sea urchins. This species can reach a length of 6.4 centimetres (2.5 in) TL. It can also be found in the aquarium trade.