Previous studies found that the zebrafish spontaneous whole-brain neuronal dynamics, obtained with Ca2+ imaging, is avalanche-like, i.e., it has alternating periods of silence and collective cascading activity bursts, where both the duration of the bursts and the number of neurons that spiked during those bursts follow power law distributions with exponents close to the random field Ising universality class, but which deviate from their critical values for avalanches occurring when there is an unbalance between excitatory (E) and inhibitory (I) activity. Here, we model the response of the zebrafish neurons in the optic tectum, displaying avalanche dynamics in spontaneous activity, to an external stimulus, aiming to see whether the power law exponents change or if the dynamics is no longer avalanche-like, and how this is related to E/I unbalances.