Granulomatous disease

This calico goldfish was unwell for a few days and had a creamy white discharge from a lesion on its left side. Post mortem examination revealed that the fish had extensive granulomas (abscesses) throughout the body and skin. This was confirmed by histopathological tests. This disease is often cause by mycobacterial infection, for which there is no effective treatment, and is a zoonotic disease (ie one that can be transmitted to humans).