What is the fine-grained topic of the following text: Sea Mullet Mugil cephalus Linnaeus 1758 Actinopterygii > Mugiliformes > Mugilidae > Mugil A bluish-grey to olive-brown mullet becoming silvery-white or paler below, with a dark-bluish spot at the base of the pectoral fin. Only return the topic.
Sea Mullet Mugil cephalus Linnaeus 1758