We employed this system to investigate, in real-time on a brain-wide scale, the onset and propagation of acute seizures, as induced by the convulsant drug pentylenetetrazol (PTZ), avoiding detrimental visual stimulation on a highly susceptible system such as an epileptic brain. At a moderate PTZ concentration we observed a widespread increase in nervous activity synchronization with the progression of the exposure time to the drug, particularly in the optic tectum, associated with an unexpected synchronization decrease happening in small spatially-defined areas. At saturating PTZ concentrations we instead observed a brain-wide functional connectivity reorganization and the emergence of distinctive phases of ictal and postictal activity. During the ictal phase the degree of synchronization in the neuronal activity dramatically increases in the whole-brain. On the contrary, the degree of neuronal synchrony in the postictal phase resembles the control condition, with the exception of the dorsal thalamus, where it increases, and subregions of the spinal cord, where it unexpectedly decreases.The volumetric frame rate of our system allowed us to observe the emergence of previously unreported fast rhythmic ictal waves propagating in postero-anterior direction, which we termed caudo-rostral ictal waves (CRIWs), spanning across the whole larval encephalon in about 1 s during the ictal phase.In conclusion, the presented 2P LSF microscope design affords high spatio-temporal resolution while avoiding visual stimuli and allows unprecedented access to whole zebrafish brain epileptic dynamics.