Pseudocapillaroides xenopi is a capillariid nematode of the epidermis of Xenopus spp. and a cause of “flaky” or “gray skin disease” in laboratory colonies. The only published regimen for eradicating it from an entire colony, which is a levamisole immersion, dates from 1997. We report its unmodified application in a colony of approximately 480 adult female X. laevis. An index animal with pale, roughened skin and severe weight loss was diagnosed by PCR. Screening all 42 cohabitants of three tanks each holding one animal with macroscopic skin abnormalities gave a prevalence of 21.4% (9/42), with seven of them clinically inconspicuous. Two four-day levamisole baths (12 mg/L) ten days apart, with tank cleaning and dedicated equipment, were applied colony-wide. Post-treatment skin scrapings were negative in 42/42 animals, gross lesions resolved, body weight was maintained and no further cases have occurred. The 1997 protocol remains fully effective. As the untreated infection is ultimately fatal and the alternative to treatment is depopulation, a regimen that reliably clears a colony is also a refinement.

Preregistration of animal studies is increasingly promoted as a methodological Refinement that can reduce bias, prevent unnecessary duplication and ultimately benefit animal welfare. Despite dedicated open registries (i.e., the Animal Study Registry of the German Centre for the Protection of Laboratory Animals (ASR) and preclinicaltrials.eu (PCT)), uptake remains low. The perceived time burden and limited awareness are the most frequently mentioned barriers, although these registries have been available since 2018 and 2019. In this feasibility study, eleven researchers (Beginners n = 3, Trainees n = 3, Experts n = 5) preregistered two preclinical protocols (rat and pig) on each platform, while completion time, mouse clicks, cursor distance, and scroll events were registered. An anonymous survey collected free-text comments. Completion time was substantially longer on ASR than on PCT for both the rat protocol (99.5 ± 29.1 vs. 39.5 ± 4.9 min) and the pig protocol (53.1 ± 17.2 vs. 25.8 ± 8.5 min), with the same direction for the other parameters. All eleven participants preferred PCT, and completion time decreased with practice. Preregistration is technically feasible on either platform. However, structured training and targeted usability improvements could reduce the activation cost and support its role as a Refinement strategy in laboratory animal science.