Abstract Aquatic ecosystems face increasingly frequent heatwaves and cyanobacterial blooms, which reduce the nutritional quality of resources available to primary consumers. This raises the question of how the nutritional quality of resources modulates aquatic ectotherm heat-induced injury accumulation and repair capacity. We address this question using Daphnia magna raised on diets of contrasting quality (rich versus poor in sterols and polyunsaturated fatty acids) by measuring heat tolerance b