Day 228 of #LMB365 was provided by Rosemary Keeble in Lalita Ramakrishnan’s group. They use zebrafish as a model organism to study human diseases such as tuberculosis. It is important to ensure the welfare of the fish and bacteria-free egg water containing the antifungal agent methylene blue is used to incubate embryos to ensure survival pre-hatching. This image shows 1 litre of egg water in a glass bottle viewed from above.