Fish

An adaptable, user-friendly score sheet to monitor welfare in experimental fish

Fish are increasingly used as experimental animals across research fields. Currently, around a quarter of all experimental animals used are fish. Less than 20% of these are standard model species. Welfare assessments for experimental fish are in their infancy compared...

Year Published: 2025Topics: Welfare AssessmentAnimal Type: Fish, Other Fish, Salmon, Shark & Ray, Tilapia, Trout, Zebrafish

Citation: Flueck-Giraud, M., Schmidt-Posthaus, H., Bergadano, A. et al. 2025. An adaptable, user-friendly score sheet to monitor welfare in experimental fish. Laboratory Animals 59(2), 226–241.

Insights from the judgement bias paradigm: Social group and tank size do not affect mental state in female guppies

Optimal holding conditions are key to animal welfare. How stressful husbandry is perceived by the animal can be determined via an assessment of an animal’s mental state – where it is positioned on the continuum between optimistic and pessimistic states...

Year Published: 2025Topics: Housing, Social Housing & Companionship, Welfare AssessmentAnimal Type: Fish, Other Fish

Citation: Epping, J., Kotrschal, A., Kotrschal, S. D. 2025. Insights from the judgement bias paradigm: Social group and tank size do not affect mental state in female guppies. Journal of Fish Biology 106(1), 12–19.

Behavioral and neurophysiological effects of electrical stunning on zebrafish larvae

Two methods dominate the way that zebrafish larvae are euthanized after experimental procedures: anesthetic overdose and rapid cooling. Although MS-222 is easy to apply, this anesthetic takes about a minute to act and fish show aversive reactions and interindividual differences,...

Year Published: 2025Topics: EuthanasiaAnimal Type: Fish, Zebrafish

Citation: Burkhardt, D.-S., Leyden, C., Thomas, C. et al. 2025. Behavioral and neurophysiological effects of electrical stunning on zebrafish larvae. Lab Animal 54(2), 50–58.

Shelter or complexity? Nile tilapia (Oreochromis niloticus) preference for enrichment structures is a matter of time and frequency of visits

Assessing fish preferences for resources may be an interesting approach to select environmental enrichments to improve their welfare. However, different operational variables may end up indicating distinct preferences. Here we investigated whether Nile tilapia (Oreochromis niloticus) express different preferences for...

Year Published: 2025Topics: Environmental EnrichmentAnimal Type: Fish, Tilapia

Citation: Maia, C. M., Montalt, A. V., Arechavala-Lopez, P. et al. 2025. Shelter or complexity? Nile tilapia (Oreochromis niloticus) preference for enrichment structures is a matter of time and frequency of visits. Applied Animal Behaviour Science 283, 106498.

Good welfare is attractive: Female zebrafish (Danio rerio) prefer males from complex, well-resourced conditions over males from conventional barren laboratory tanks

Applied ethologists often find that sub-optimal housing (e.g. barren versus “enriched”, well-resourced conditions) impairs animals’ interactions with conspecifics. Furthermore, some housing effects on social/sexual interactions persist even in standardised test situations. For example, in mating tests on three mammalian and...

Year Published: 2025Topics: Environmental Enrichment, ReproductionAnimal Type: Fish, Zebrafish

Citation: Lavery, J. M., Snaith, K., Pallarca, J. et al. 2025. Good welfare is attractive: Female zebrafish (Danio rerio) prefer males from complex, well-resourced conditions over males from conventional barren laboratory tanks. Applied Animal Behaviour Science 286, 106603.

Effects of social enrichment induced by different-sized groups and live bait on growth, aggressive behavior, physiology, and neurogenesis in juvenile Sebastes schlegelii (2025)

This study examined the effects of stress and social enrichment on fish neuroplasticity and antioxidant capacity, addressing growing concerns about fish welfare in aquaculture. A 2 × 2 × 2 factorial design comprising eight treatment groups was implemented to investigate...

Year Published: 2025Topics: Social Housing & CompanionshipAnimal Type: Fish, Other Fish

Citation: Zhang, Z., Yu, X., Wu, Z. et al. 2025. Effects of social enrichment induced by different-sized groups and live bait on growth, aggressive behavior, physiology, and neurogenesis in juvenile Sebastes schlegelii. Fishes 10(5), 242.

Quantifying the welfare impact of air asphyxia in rainbow trout slaughter for policy and practice (2025)

The effective improvement of animal welfare requires quantitative methods to compare diverse impacts across practices and policies on a common, relatable scale. The Welfare Footprint Framework (WFF) fulfills this need by providing a standardized welfare impact measure: cumulative time in...

Year Published: 2025Topics: EuthanasiaAnimal Type: Fish, Trout

Citation: Schuck-Paim, C., Alonso, W. J., Pereira, P. A. et al. 2025. Quantifying the welfare impact of air asphyxia in rainbow trout slaughter for policy and practice. Scientific Reports 15(1), 19850.

Novel euthanasia technique for zebrafish using electric shock in standard group housing aquaria

Zebrafish are widely used in research, accounting for approximately 50% of all laboratory fish across Europe. Due to their rapid reproduction and aging, effective and practical euthanasia methods are necessary for managing large stocks. This study investigated whether adult zebrafish...

Year Published: 2025Topics: EuthanasiaAnimal Type: Fish, Zebrafish

Citation: Saarinen, U., Sundell, E., Sneddon, L. et al. 2025. Novel euthanasia technique for zebrafish using electric shock in standard group housing aquaria. Scientific Reports 15(1), 3011.

Early-life environmental enrichment promotes positive animal welfare for juvenile Atlantic salmon (Salmo salar) in aquaculture research (2025)

Early life experiences have long-lasting effects on behaviour and physiology, influencing development of adaptive natural behaviours. Enriching farmed environments encourages expression of natural behaviours in captive fish, promoting positive animal welfare, important for conducting valid and reproducible research and informing...

Year Published: 2025Topics: Environmental EnrichmentAnimal Type: Fish, Salmon

Citation: Prentice, P. M., Chivite Alcalde, M., Císař, P. et al. 2025. Early-life environmental enrichment promotes positive animal welfare for juvenile Atlantic salmon (Salmo salar) in aquaculture research. Scientific Reports 15(1), 5828.

Tricaine, eugenol and etomidate for repetitive procedural anesthesia in adult zebrafish, Danio rerio: Effect on stress and behavior (2025)

Zebrafish has emerged as a popular animal model in biomedical research. Numerous procedures and interventions require occasionally repetitive anesthesia. Tricaine is the most frequently used anesthetic for zebrafish and its efficacy is well established. However, the safety and efficacy of...

Year Published: 2025Topics: Anesthesia & SedationAnimal Type: Fish, Zebrafish

Citation: Narumanchi, S., Perttunen, S., Laine, P. et al. 2025. Tricaine, eugenol and etomidate for repetitive procedural anesthesia in adult zebrafish, Danio rerio: Effect on stress and behavior. Frontiers in Veterinary Science 12.