Current hydro power turbine technology is reviewed regarding safe fish passage. Much of the literature has focused on dam turbine configurations, while some have recommended to develop in-stream turbines as an alternative and potentially more environmentally- and ecologically-friendly option. Throughout the literature, several key design parameters and considerations appear consistently, with which future turbines are recommended to be designed if installed near fish habitats or migratory routes. Design parameters and recommendations are compiled and examined here, and conclusions about future developments of hydro turbines are provided. Additionally, the criteria and considerations are applied to an in-stream turbine design, which is shown to exhibit fish-friendly operation over a wide range of riverine velocities with mitigated fish access to the tip region. It is shown that in-stream turbines are a future-friendly (environmentally, ecologically and socially) technology that can provide sustainable energy generation to people throughout the world as an alternative to dams, including those in off-grid communities with little-to-no access to electricity.