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Pharmaceuticals are essential for human well‐being, but their increasing and continuous use pollutes the environment. Although behavioral ecotoxicology is increasingly advocated to assess the effects of pharmaceutical pollution on wildlife and ecosystems, a consensus on the actual environmental risks is lacking for most compounds. The main limitation is the lack of standardized reproducible tests that are based on sensitive behavioral endpoints and that accommodate a high ecological relevance. In the present study, we assessed the impact of a 3‐wk exposure to the antidepressant fluoxetine on multiple behavioral traits in the promising new model organism Nothobranchius furzeri (turquoise killifish). Overall, our study shows that fluoxetine can impact feeding behavior, habitat choice in a novel environment, and antipredator response of N. furzeri individuals; effects on spontaneous activity and exploration tendency were less pronounced. However, effects became only apparent when individuals were exposed to fluoxetine concentrations that were 10 times higher than typical concentrations in natural aquatic environments. Ecotoxicologists are challenged to maximize both the reliability and ecological validity of risk assessments of pollutants. Our study contributes to the development of a time‐ and cost‐efficient, standardized ecotoxicological test based on sensitive, ecologically relevant behavioral endpoints in N. furzeri. Environ Toxicol Chem 2019;38:262–270. © 2018 SETAC [ABSTRACT FROM AUTHOR]

Global warming and environmental pollution threaten aquatic ecosystems. While interactive effects between both stressors can have more than additive consequences, these remain poorly studied for most taxa. Especially chronic exposure trials with vertebrates are scarce due to the high time- and monetary costs of such studies. We use the recently-established fish model Nothobranchius furzeri to assess the separate and combined effects of exposure to the pesticide chlorpyrifos (at 2 µg/L and 4 µg/L) and a 2 °C temperature increase. We performed a full life-cycle assessment to evaluate fitness-related endpoints including survival, total body length, maturation time, fecundity, critical thermal maximum (CTmax) and locomotor activity. Exposure to 4 µg/L chlorpyrifos slowed down male maturation, reduced fecundity and impaired growth of the fish. While the temperature increase did not affect any of the measured endpoints on its own, the combination of exposure to 2 µg/L CPF with an increase of 2 °C reduced growth and severely reduced fecundity, with almost no offspring production. Together, these findings suggest that climate change may exacerbate the impact of environmental pollution, and that interactive effects of chronic exposure to multiple stressors should be considered to predict how populations will be affected by ongoing global change. • Studying effects of long-term exposure is time-efficient with annual killifish. • Exposure to 4 µg/L chlorpyrifos affected growth, male maturation time and fecundity. • Effects emerged at a lower chlorpyrifos concentration when fish experienced temperature stress. [ABSTRACT FROM AUTHOR]

As many freshwaters are chemically polluted, one of the challenges for policy makers is to determine the potential impact of these pollutants on ecosystems and to define safe concentrations. Common practice is the use of ecotoxicological assays to assess the response of model organisms from different trophic levels such as algae, invertebrates and fish during exposure to dilutions of a specific compound. Ideally, ecotoxicological assessments of (pseudo-)persistent chemicals should be performed across the life-cycle or even multiple generations for an accurate risk assessment. Multigenerational tests with fish are, however, impractical and costly given the long lifespan and generation time of classic model species. Here, we suggest a framework for more relevant, time- and cost-efficient fish-based testing in ecotoxicology and align it with accredited test guidelines. Next, we introduce an upcoming fish model, the turquoise killifish Nothobranchius furzeri, and show how it facilitates such research agendas due to a short lifespan and generation time. Through a review of fish-based exposure studies with a set of reference toxicants, we position N. furzeri as a sensitive species, suitable for screening effects of different pollutant types. Ultimately, we perform a cost-benefit analysis and propose a plan of action for the introduction of N. furzeri into accredited test guidelines. • We provide an overview of current issues with fish-based testing in ecotoxicology. • We suggest a framework for relevant, time- and cost-efficient fish-based testing. • We showcase killifish as a sensitive model for chronic and multigenerational tests. • We identify future research perspectives to integrate the model in accredited tests. [ABSTRACT FROM AUTHOR]