The importance of steroidogenesis is underscored by its vital and conserved functions from higher to lower vertebrate species, such as stress, immune and inflammatory responses, sexual development and reproduction, osmoregulation and even the ability to adapt to the environment and environmental changes. Correspondingly, the rate-limiting step of steroidogenesis mediated by the steroidogenic acute regulatory protein is an ongoing target for scientific investigation. An expanding collection of studies has now reported key similarities, as well as some differences, in the transcriptional and translational regulation of steroidogenic acute regulatory protein across species. This review will discuss the current understanding of steroidogenic acute regulatory protein in fish, as these lower vertebrate models uniquely rely on steroid hormones for osmotic balance, reproductive functions, responses to environmental stimuli and much more.