Environmental Enrichment Strategies for Fish Welfare

Environmental enrichment strategies aim to mimic natural habitat features and stimuli within captive settings to promote the behavioural, physiological and cognitive health of fish. By introducing structural complexity, varied substrates, shelters, social companions or microbial heterogeneity, these interventions seek to reduce stress, aggression and stereotypic behaviours while encouraging natural foraging, exploration and social interactions. Enrichment can be implemented at multiple life stages and in diverse aquaculture and research contexts, from hatcheries to large-scale production systems. Key outcomes include improved immune responses, enhanced neural development, greater environmental adaptability and reduced mortality during disease outbreaks or acute stress. Effective enrichment strategies balance practicality and cost with ecological relevance, recognising species-specific behavioural repertoires and environmental preferences. Global demands for sustainable aquaculture and responsible animal use in research have driven innovation in enrichment design, integrating insights from neurobiology, physiology and microbiology. Interdisciplinary collaboration and standardised welfare metrics are essential to refine protocols and translate experimental findings into commercial practices, ensuring fish are offered conditions that support their intrinsic needs and welfare.

Research from Nature Portfolio

Recent studies have demonstrated the long-term benefits of environmental enrichment in juvenile Atlantic salmon and gilthead seabream. Trials with early-life structural complexity in Atlantic salmon revealed that provision of shelters and substrate during larval stages enhanced group cohesion, reduced neophobic responses and elevated markers of neuroplasticity and serotonergic activity following stress. Enriched salmon exhibited upregulation of genes linked to neuronal development and stress resilience, suggesting improved emotional states and cognitive flexibility. In gilthead seabream, structural enrichment using plant-fibre ropes within tanks led to increased exploratory behaviour, spatial learning and orientating efficiency in maze experiments. Brain monoamine analyses indicated heightened dopaminergic and serotonergic turnover associated with reward and motor coordination, while antioxidant assessment pointed to reduced oxidative stress in enriched fish. These findings underline the capacity of enrichment to bolster cognitive function, stress coping and welfare in aquaculture species.

Environmental Enrichment Strategies for Fish Welfare publication trend

The graph below shows the total number of articles in environmental enrichment strategies for fish welfare across all publications each year (not limited to Nature Index journals).

Technical terms

Environmental enrichment: The addition of physical, social or sensory stimuli to captive environments to promote natural behaviours and welfare.

Neophobia: The avoidance or fear of novel objects or environments, often used as an indicator of emotional state in animals.

Neuroplasticity: The capacity of the nervous system to reorganise its structure, function and connections in response to experience and environmental stimuli.

Microbial diversity: The variety and abundance of micro-organisms in a given habitat, influencing host health and disease resistance.

Social enrichment: The provision of conspecific or heterospecific interactions in captive settings to support natural social behaviour and reduce stress.

References

1. Heterogeneity of the rearing environment enhances diversity of microbial communities in intensive farming. Animal Microbiome (2024).
2. Early-life environmental enrichment promotes positive animal welfare for juvenile Atlantic salmon (Salmo salar) in aquaculture research. Scientific Reports (2025).
3. Enriched environments enhance cognition, exploratory behaviour and brain physiological functions of Sparus aurata. Scientific Reports (2020).
4. Effects of simple shelters on growth performance and welfare of rainbow trout juveniles. Aquaculture (2022).
5. Social enrichment affects fish growth and aggression depending on fish species: Applications for aquaculture. Frontiers in Marine Science (2022).