Best practices in Xenopus Housing, Husbandry and the 3Rs v1

***** This is a preprint of the following chapter Authors: Anna Noble, Gretel Nicholson, Billie Dolphin, Mel Ersin and Esther J. Pearl Chapter: Chapter 1 - Best practices in Xenopus Housing, Husbandry and the 3Rs Book title: Xenopus protocols (part of the Methods in Molecular Biology series) Edited by Caroline W. Beck Publisher: Springer Nature. Expected publication in 2026. Once the book is published a link to the final version will be added to a version of this protocol. This is the version on the author's manuscript prior to acceptance for publication and has not undergone editorial and/ or peer review on behalf of the publisher. ***** Appropriate housing and husbandry practices for laboratory Xenopus are key to maintaining good welfare standards and generating reliable experimental results. Although we lack empirical evidence for many housing and husbandry practices, Xenopus have been used as a laboratory species for decades. As a result, best practices have evolved over time as researchers and staff at frog facilities have built up experience on what helps to keep frogs in the best condition. Different Xenopus species have different care needs, this chapter covers housing and husbandry protocols for Xenopus laevis and Xenopus tropicalis. These are the current protocols of the European Xenopus Resource Centre (EXRC) in Portsmouth, United Kingdom. The EXRC provides services supporting researchers using Xenopus in research, including guidance on housing, husbandry, breeding and colony management and maintaining healthy frogs to enable collection of reliable data. Here, we describe how to set up and seed a new recirculating system, surface sterilisation of embryos and identification of individual frogs. We also outline best practices for each life stage, including indicators of good health and normal behaviour as well as signs of distress or poor health and protocols for handling disease outbreaks.