In channelized and structurally simple temperature streams and rivers, adverse winter conditions may challenge the ability of riverine fishes to adapt in terms of their behaviour and physiology. Access to shelter is a key habitat factor that may influence overwinter survival chances and, consequently, population dynamics. In many river restoration projects, structural elements are added to the river to increase the complexity of the physical environment. When this habitat enhancement is combined with a stocking programme, the stocked fish mayadopt different behavioural strategies to cope with the winter season depending both onthe rearing environment in the hatchery and the level of habitat complexity in the river. In this study, young-of-the-year brown trout were reared in either barren or structurally enhanced tanks, and the effects of the rearing environment on resting ventilation rate (proxy for resting metabolic rate) and score in an open field test (proxy for activity) were assessed. In side channels of a Swedish regulatedriver, trout were then released at untreated control sites or at sites that were structurally enhanced by adding whole trees to the water. Throughout winter, trout were tracked on a weekly basis, and their movements as influenced by the river habitat complexity and the previous hatchery environment were analysed. The rearing environment affected resting metabolicrates and activity, which resulted in different behavioural overwintering strategies, and adding trees to the side channels increased apparent survival. These results have implications for managing river restoration projects and further studies of stream fish winter ecology.