In many research studies, the handling and procedures performed can generate stress and require the use of anesthesia or sedation. In this sense, plant-based extracts named essential oils have emerged as potentially effective and environmentally safe anesthetic/sedative options. Here, we sought to evaluate the essential oil of Varronia curassavica (VCEO) as an anesthetic/sedative ingredient. Here, the anesthetic and sedative capabilities of the VCEO using adult zebrafish (Danio rerio). The anesthetic induction was performed under four different concentrations (100, 200, 400, and 600 mg L-1), followed by evaluation of recovery time; furthermore, a 3 h long exposure was performed for sedative testing, where fish were exposed for 3 h at three different concentrations (50, 80, and 100 mg L-1) under a superpopulation condition, such as those faced during transport. To assess stress, we collected whole-body cortisol from each individual after each exposure. The concentrations of 400 and 600 mg L-1 induced anesthesia (S4) but promoted excessive recovery times; on the contrary, they reduced the cortisol levels of the fish compared with the positive and negative controls. In the sedative testing (3 h long exposure), the animals exposed to 50 mg L-1 remained in S2 stage from the first 10 min, and those exposed to 80 mg L-1 after 20 min. The 100 mg L-1 induced stage S3a. There were no significant changes in cortisol levels observed at these concentrations. Limitations include measurement of whole-body cortisol at a single endpoint and the consistently slower induction and recovery with VCEO compared with a reference anesthetic MS-222, a property that constrains its practical use and warrants further dose-response, time-course, and recovery-optimization studies. Therefore, VCEO appears to be a promising anesthetic and sedative alternative, effective and plant-based, without increasing the physiological stress of the animals.

The African turquoise killifish, Nothobranchius furzeri, has emerged as an important vertebrate model for aging research due to its naturally short lifespan and hallmarks of aging. However, these characteristics create challenges for colony management, such as high breeder turnover, rapid generational change, and the risk of inbreeding or unintended selection in closed laboratory populations. Since new individuals cannot be introduced from the wild or purchased from commercial laboratory animal breeders, maintaining genetically stable laboratory stocks requires carefully controlled breeding strategies. Here, we describe an innovative colony management approach termed dynamic population breeding (DPB) and evaluated its performance in two commonly used laboratory lines with different lifespans, GRZ-D and MZCS-08/122. DPB integrates several key principles: the maintenance of overlapping breeding age cohorts, harem-based breeding groups, continuous monitoring of clutch quality and quantity, and the controlled use of embryonic diapause for flexible embryo storage and synchronized hatching. Embryos from multiple breeding groups were pooled, stored in diapause stage II, and hatched at defined time points to generate new cohorts while avoiding sibling-only populations. Using this approach, we systematically analyzed reproductive performance, embryo quality, hatching success, and survival in laboratory populations. Fertilization rates and clutch sizes remained within stable ranges across the reproductive period, although an age-dependent decline in fertilization efficiency was observed in both lines. Quality control at the clutch level allowed early identification and exclusion of low-performing breeding groups. Importantly, implementation of DPB reduced variability between cohorts and improved early-life survival of offspring, particularly during the first weeks after hatching. Overall, DPB provides a practical framework for maintaining stable and robust killifish colonies while minimizing unintended selection and inbreeding. By integrating diapause biology with structured breeding management, this strategy enhances reproducibility and sustainability of N. furzeri populations used in aging research.

Hawai'i and other island communities around the globe are experiencing high exposures to micro- and nanoplastics (MNPs). Widespread use of various types of plastics and the action of wave physics coupled with abundant silica creates a constant production of MNPs. The community health effects of exposure to MNPs are not yet fully understood. The aquatic vertebrate model zebrafish, Danio rerio, was utilized to evaluate the developmental and behavioral effects of nanoplastic (NP) exposure as well as visual confirmation of plastic accumulation after embryonic and larval exposure. Eye and yolk size, heart rate, angle of development, and early larval locomotion behavior were quantified after early NP exposure lasting 3 or 5 days. In this work, a digital laboratory environment is used as the context for research trainees spanning high school to graduate and medical school in Hawai'i to explore health outcomes of developmental NP exposures. Presence of MNPs in the early developmental environment led to changes in growth and behavior of exposed fish. Data analysis showed significant effects of exposures on changes in the rate of development and yolk consumption on day 2 and reduced body length and increased locomotion on day 6. Nanoplastic exposure also affected overall body length, but this effect was not significant. These data support the potential dangers of MNP exposure and demonstrate their persistent detrimental effects on development and behavior in young zebrafish. Accordingly, our work contributes toward shifting focus toward understanding longer impacts on health, growth, and behaviors and potentially the reduction of harm in developing vertebrates.

This study presents a comprehensive bibliometric analysis of zebrafish (Danio rerio) research published between 2000 and 2025, based on data retrieved from the Web of Science Core Collection and analyzed using Clarivate's InCites platform. A total of 74,675 records were examined to uncover trends in publication volume, geographical and institutional distribution, international collaborations, disciplinary coverage, and thematic evolution over time. The results indicate a steady growth in zebrafish-related publications, particularly between 2000 and 2021, followed by a relative plateau. The United States and China lead in research output, with China showing rapid growth over the last decade. Collaboration networks remain dominated by a limited number of high-capacity countries, while many others, particularly those with limited infrastructure, remain underrepresented. The Cooperation in Science and Technology Member Countries also showed a noticeable decline in publication numbers following a 2021 peak. Thematic keyword analysis revealed a clear shift from early developmental biology themes-such as hindbrain and retinal development-toward emerging topics such as regeneration, oxidative stress, and toxicology. However, the findings suggest that this thematic diversification has not yet translated into widespread interdisciplinary integration. Zebrafish research remains largely anchored within classical biological disciplines, despite its increasing relevance to fields such as neuroscience, environmental health, pharmacology, and biomedical engineering. This mismatch between thematic scope and interdisciplinary adoption represents a potentially missed opportunity-especially in addressing complex global challenges. Strengthening cross-disciplinary collaborations and promoting the adoption of zebrafish in innovative, technology-driven research contexts may help unlock the full strategic potential of this versatile model organism.

Conducting longitudinal experiments on zebrafish disease models has the potential to deepen understanding of disease progression. Longitudinal experiments require rearing of zebrafish embryos/larvae in the laboratory for extended time periods to enable use of laboratory equipment for serial observation. We observed that in our laboratory, wild-type larvae did not survive past 14 days. As we were unable to identify a study that compared different factors that could affect survival of larvae raised in the laboratory, we aimed to define the most relevant parameters that impact larval survival and growth. We found that prolonged access to food had the greatest beneficial effect on survival, regardless of rearing density or rearing media. However, rearing density did impact the activity of 2.5-week-old larvae. Methylene blue is a frequent additive to zebrafish embryo-rearing medium. Methylene blue can impact cellular health, and methylene blue mitigated the decrease in motility of densely grown larvae. Methylene blue also promoted growth: larvae raised in methylene blue were significantly larger at 1 month than their counterparts raised without methylene blue. These data highlight factors that promote survival and growth of larval zebrafish raised in the laboratory for longitudinal studies.

The skin barrier function is essential for maintaining skin health. Consequently, it is crucial to evaluate the protective and restorative effects of topical medications and cosmetics on the skin barrier. However, methods that can directly assess the skin barrier function in zebrafish beyond their regenerative capabilities are limited. Therefore, we aimed to develop an invivo, in situ, high-throughput screening model for assessing skin barrier function in zebrafish embryos. Lactic acid was used to induce skin barrier damage and crystal violet was used for staining to observe skin barrier damage. Histopathology was assessed using H&E, Masson, and Victoria blue staining. Cellular apoptosis was evaluated using in situ acridine orange (AO) staining and flow cytometry with propidium iodide (PI) staining. A significant increase was noted in fluorescence in the trunk and tail regions of zebrafish embryos following lactic acid stimulation compared with those in the control group, whereas exposure to the positive control for 4 h significantly reduced the fluorescence area, showing 35%-45% inhibition. Histological sections revealed that lactic acid caused noticeable damage to the epidermis of zebrafish embryos, characterized by thinning of the epidermal layer and the presence of inflammatory cell infiltrates. An increase in apoptotic cells was observed through in situ AO and PI staining using flow cytometry, and RT-qPCR revealed elevated expression levels of apoptosis-related genes, including fas, bax, and caspase 3. Furthermore, six additional samples from various sources were screened using this model, which yielded reasonable outcomes for both positive and negative samples, indicating its potential application value in evaluating the skin barrier protective efficacy of drugs or compounds. Our study supports the use of the lactic-acid-induced zebrafish skin injury model as a reliable invivo and in situ method for evaluating skin barrier function.

The zebrafish (Danio rerio) is a commonly used model organism for human diseases due to its genetic similarities with humans since over 80% of genes associated with human diseases are also found in the zebrafish. For most genetic experiments, it is essential to gather tissue for genotyping in a nonlethal procedure. A common method is removing a part of the tail fin from individual adult zebrafish with a scalpel. The fin usually regenerates within 14 days, leaving the fish without permanent damage. However, larval genotyping might offer significant advantages, such as saving resources and reducing the number of research animals and enabling experiments on zebrafish embryos with a specific genotype. Here, we show a cost-efficient method for fin-clipping zebrafish embryos as early as 48 h postfertilization (hpf). When done correctly, the fin will regrow quickly, being nearly completely restored at 120 hpf. While the amount of extracted DNA is low, it is still sufficient for commonly used methods of genotyping. Embryos with the desired genotype can then be used for phenotypic or functional analyses or be raised to adulthood.