Embryo incubation is often treated as a routine husbandry step in zebrafish facilities, yet sensitive transgenic lines may not respond to standard protocols like robust wild-type stocks. The effects of feasible changes in incubation medium and embryo density on developmental performance and between-plate variability were evaluated in Tg(kop:7a-dsRed-nos3′UTR), a line showing variable output under routine conditions. Embryos were incubated in E3 medium or recirculating aquaculture system (RAS) water at 25, 50, or 100 embryos per Petri dish. Survival, hatching, larval length, and morphological abnormalities were integrated into a Baseline-calibrated Developmental Index (BDI), using wild-type AB embryos as an in-house reference. All Tg(kop) conditions remained below the wild-type baseline, with mean BDI_abs values of 0.540–0.650 compared with 0.916 in wild type. E3 tended to support higher mean developmental performance, but with greater between-plate variability. RAS water produced lower mean BDI values with lower observed between-plate variability. Embryo density showed no clear directional effect under daily-care conditions. These results indicate that sensitive transgenic lines may require dedicated incubation phenotyping, and that baseline-calibrated multiparametric assessment can help distinguish protocols that differ in mean output and observed plate-to-plate variability.
Zebrafish husbandry regimens often use live rotifers or paramecia during the first 2 weeks of larval feeding. The rationale is that the small larval gape requires suitably small prey. As larvae grow, they are transitioned to feeding on larger prey in the form of brine shrimp ( Artemia ). Typically, the Artemia used are the San Francisco Bay (SFB) strain. This strain is reported to be smaller than the Great Salt Lake (GSL) strain and is presumably easier for larvae to capture. Here, we tested the ability of zebrafish larvae to capture either strain. Daily, from 5 to 15 days post-fertilization (dpf), intestinal contents were imaged through the body wall of live larvae following shrimp feeding. Larvae showed increased capture success day by day, and by 9 dpf most larvae captured the SFB strain. By contrast, few larvae captured the GSL strain throughout the study. Morphometric tests comparing the strains showed no differences in length or width for newly hatched shrimp. However, after 48 h of culturing, the GSL strain was significantly larger than the SFB strain. For husbandry regimens that omit rotifers or paramecia and introduce shrimp from the first feeding, these results highlight the importance of using newly hatched SFB Artemia .
Intraocular pressure (IOP) monitoring is a critical aspect of diagnosis, and management of ocular diseases. Therefore, a tractable vertebrate model capable of reliable IOP characterization is highly desirable. The present study aims to perform a preliminary investigation of a handheld rebound tonometer to stably measure IOP and further characterize baseline IOP values in the zebrafish model. The IOP in both eyes (oculus dexter, OD, and oculus sinister, OS) of wild-type zebrafish was measured using the iCare PRO rebound tonometer at the same time points on testing days for 18 months. The long-term IOP values of male zebrafish (3-21 months) were range from 21.96 ± 0.99 to 23.39 ± 0.32 mm Hg (OD) and 22.10 ± 0.93 to 23.38 ± 0.26 mm Hg (OS), while insignificant difference was noted among testing days (p > 0.05). Similarly, insignificant difference was observed in female zebrafish with IOP values range from 22.10 ± 1.12 to 23.19 ± 0.72 mm Hg (OD) and 22.30 ± 1.00 to 23.15 ± 0.36 mm Hg (OS) (p > 0.05). A comprehensive evaluation of IOP profiles confirmed no significant differences based on gender, time point, and between eyes. These findings indicated that our iCare tonometer-based experimental methods provide high measurement and time-point consistency, confirming their long-term reproducibility and reliability in measuring IOP in the zebrafish.
Zebrafish are a powerful, accessible vertebrate model for teaching core biology concepts. BioEYES is a well-established K-12 outreach program that uses inquiry-based classroom investigations to leverage these strengths. However, its traditional model relies on dedicated personnel and substantial infrastructure, limiting sustainability at individual institutions. Here, we describe UCI BioEYEs, a graduate student-led adaptation that maintains BioEYES' educational strengths while reducing logistical and financial barriers. In partnership with middle school science teachers at a dual-language (English-Spanish) campus, UCI BioEYEs delivers week-long modules built around live zebrafish embryos and larvae. Graduate students lead hands-on investigations in cell biology, development, environmental effects on embryogenesis, and Mendelian inheritance. Activities use standard classroom equipment (e.g., school-grade stereoscopes, smartphone-based imaging), enabling repeated use without specialized infrastructure. Over four years, UCI BioEYEs reached over 1,100 middle school students. Teachers cited curriculum integration, sustained engagement with live vertebrate models, graduate student role models, and inclusive bilingual design as key to long-term adoption. Graduate instructors reported major gains in teaching confidence and science communication skills. Thus, a graduate student-led structure sustains zebrafish-based outreach benefiting K-12 learners while supporting graduate training. UCI BioEYEs offers a transferable framework for scalable, inclusive science education. All curricular materials are provided here to support adoption by other institutions.
Zebrafish are an emerging vertebrate model for traumatic brain injury (TBI) research, but current larval injury paradigms, especially weight-drop methods, can be difficult to standardize. Here, we describe the Zebrafish Pneumatic Injury Device (ZePID), a compact pneumatic piston system that delivers controlled, reproducible pressure pulses to induce TBI in larval zebrafish. ZePID showed a strong linear relationship between input and delivered pressure and reduced variability relative to weight-drop approaches. In 6-days postfertilization larvae, a 150 psi injury increased maximum swimming speed and total distance traveled, consistent with seizure-like hyperactivity after TBI.
