Knowing the kinds of physical stress experienced by fish passing through hydropower turbines can help optimise technologies and improve fish passage. This paper assesses the hydraulic conditions experienced through three different low-head turbines, taken using an autonomous sensor: a VLH, Archimedes screw and horizontal Kaplan turbine. A total of 127 Sensor Fish deployments were undertaken across all three turbines, generating 82 valid datasets. Decompression was rare at the VLH and screw turbines and rarely fell more than 10 kPa below atmospheric pressure. In contrast, the Kaplan was capable of generating pressures as low as 55.5 kPa (approximately 45 kPa below atmospheric pressure), over shorter periods of time. Severer ratios of pressure changes could therefore be expected for both surface and depth acclimated fish at the Kaplan when compared to the other turbines. Strike was another possible source of fish injury (detected in 69-100% of deployments), and although strike severity was highest at the Kaplan, strike was more likely to be encountered at the screw and VLH than the Kaplan turbine. Shear only occurred near the blades of the Kaplan and not at severe levels. The results demonstrate that low-head hydropower facilities are not without their risks for downstream migrating fish.