What can I eat before being eaten? Notes about the diet of Phoxinus spp. in a high mountain lake (Monviso group, NW Italy)

High mountain lakes are naturally fishless and therefore particularly vulnerable to the introduction of non-native fish. In addition to salmonids, minnows Phoxinus spp. have recently been introduced into these environments. While the impact of salmonid introductions on biodiversity has been extensively studied, including analyses of their diet, information on the impact and diet of introduced minnows in these environments remains scarce. This study analyzes the stomach contents of minnows in a high mountain lake, demonstrating how their diet reflects the low diversity of aquatic fauna typical of these oligotrophic environments, as well as the overexploitation of natural communities resulting from the unnatural presence of fish. This information can be useful for better understanding the complex ecological dynamics that arise when multiple predators are introduced into sensitive and unique environments such as high mountain lakes.