Aquaponics or the integration of aquaculture and hydroponic farming, is a sustainable food production system that is currently popular more as a hobby rather than on commercial scales. Recent increase in scientific and public interest in aquaponics and its environmental benefits supports research that addresses technical, economic, and legislative barriers to wider adoption of these systems. A successful combination of hydroponics with an aquaculture system requires high levels of knowledge and skill that are not necessarily available to all aquaponic practitioners. In this short communication, we analyzed the results of a worldwide survey of commercial aquaponic growers' statements about their own knowledge base. Most respondents (59%) had some relevant prior knowledge. Surprisingly, many respondents (41%) claimed to have insufficient knowledge of both fish and plants in their first year of operating a commercial aquaponics system. We interpret this as a rough indication that about a third of the new aquaponic businesses are started by entrepreneurs who are not farmers and have no prior training or experience in growing fish or plants. If aquaponics is to become a more widespread commercially viable enterprise and be capable of delivering its environmental benefits, its promotion must consider the importance of prior knowledge held by entrepreneurs entering aquaponics.