The process whose specific outcome is the progression of the cupula over time, from its formation to the mature structure. The cupula is secreted by mantle cells and the ciliary bundles of all of the hair cells of the neuromast are embedded in it. The cupula provides a mechanical linkage between the hair cells and the external hydrodynamic environment. The cupula of superficial neuromasts grows continuously, while the height of the cupula of canal neuromasts is limited by canal diameter.