General mechanisms of motor network development have often been examined in the spinal cord because of its relative simplicity when compared to higher parts of the brain. Indeed, most of our current understanding of motor pattern generation comes from work in the lower vertebrate spinal cord. Nevertheless, very little is known about the initial stages of motor network formation and the interplay between genes and electrical activity. Recent research has led to the establishment of the zebrafish as a key model system to study the genetics of neural development. The spinal cord of zebrafish is amenable to optical and electrophysiological analysis of neuronal activity even at the earliest embryonic stages when the network is immature. The combination of physiology and genetics in the same animal model should lead to insights into the basic mechanisms of motor circuit formation. This paper reviews recent work on the development of zebrafish motor activity and discusses them in the context of the current knowledge of embryonic and larval zebrafish spinal cord morphology and physiology.