Individual differences (IDs) in behavior among nonhuman animals have been documented in a wide range of taxa. Although traditionally considered noise around an average, other potentially adaptive sources of phenotypic variation exist. IDs in behavior that are consistent across time and context are more recently recognized as expressions of underlying personality traits, which may even be heritable. Unfortunately, despite the rapid advances that have been made in animal personality research utilizing fish the last decade, a few have detailed the groundwork necessary to document consistency in behavior across time and context. This foundation is required, by definition, before one can draw conclusions about personality traits. Here, we examine whether IDs in behavior are consistent over time and across contexts and explore the construct validity of six commonly used behavioral assays for examining four personality traits: aggression, boldness, fear, and exploration. Thirty zebrafish (Danio rerio) were exposed twice each to a small open field, large open field, mirror, emergence, novel object, and predator response test. Results revealed consistency in most behavioral measures across both time and context. There was mixed evidence for the construct validity of these assays in capturing the targeted personality traits.

Zebrafish are at the forefront of neurobiological research and have been gaining popularity as a viable and valid behavioral model in a variety of research applications (e.g., assessing drug induced behavioral changes). This model becomes even more attractive when considering the behavioral changes that follow exposure to compounds that are water-soluble. As such, several studies have implicated both acute and chronic ethanol exposure in the modulation of zebrafish behavior. Within this arena there appears to be a common trend across multiple studies. As with many drugs ethanol appears to influence behavior in a dose-dependent manner. In this review, we compare and contrast several studies that measure behavior as a result of alcohol exposure. Appended to this review are pilot data that report zebrafish blood alcohol concentrations as a function of acute exposure.

The authors would like to thank those who have encouraged interest in the animal personality field and have been available to answer questions and for discussion, including Stan Kuczaj and Lauren Highfill. We apologize to our colleagues whose work we did not cite due to page limitations.

Photo analysis offers a simple, noninvasive approach to characterizing and quantifying skin lesions in cetaceans; however, this process involves methodological considerations that have often gone unaddressed or have varied in approach among investigators. Subjectivity associated with classifying skin lesion types of unknown etiology and quantifying measures of skin lesion prevalence and extent from photo data raises questions about observer bias and agreement (i.e., interrater reliability), which are often ignored. The purpose of the present study was to improve upon data quality control and assessment practices when studying skin lesions using only photo data. Specifically, we tested interrater reliability of a skin lesion classification system, compared methods of quantifying skin lesion extent, and determined the validity of the dorsal fin as a proxy for skin lesions on the entire body. Acceptable levels of interrater reliability were achieved for only 7 of 17 defined lesion types, but reliability was high for the two tested measures of lesion extent. Skin lesion extent measured from the dorsal fin alone was not a decent proxy for the whole visible surface; disparities between measures were as high as 43%. We discuss the potential pitfalls discovered and provide recommendations for others attempting similar approaches.