Ultrastructural study of the thymus of Mugil liza Valenciennes, 1836 juveniles.

•Mugil liza is a species with potential production in aquaculture.•It is a spice that suffers from various diseases.•Knowing your immune system is important for this activity.•Electron microscopy unlike optical microscopy allows to study in detail the different types of cells that compose it.•Electron microscopy allows evaluating thymus histiogenesis .