Veterinarija ir Zootechnika

Koi carp (Cyprinus carpio var. koi) are globally popular ornamental fish, valued for their distinctive coloration and patterns. However, infectious disease outbreaks remain an important health concern, particularly bacterial infections associated with skin ulceration, systemic disease, and mortality. Motile aeromonad infections in freshwater fish, including koi carp, have traditionally been attributed mainly to Aeromonas hydrophila, while other species may have been underdiagnosed or overlooked. In this report, we describe the isolation of Aeromonas veronii from koi carp in a private collection presenting with lesions consistent with koi ulcer disease, together with the associated macroscopic findings.

In the 20th century, wild otter populations declined across the world. This decline was associated with several factors, such as habitat destruction and hunting. Other underlying causes were anthropogenic contaminant loads in their food and water sources. Aquatic mammals such as otters are very susceptible to chemical contamination and, as top predators, can be considered sentinel species for the health of the ecosystem. This brief review aims to show the presence of environmental contaminants in different otter species and how they may have contributed to the population decline of these species. Although many studies have been carried out on the presence of these compounds in otters, in the future, it is important to continue monitoring these populations to understand their impacts under the One Heath concept.