First record of intraspecific cleaning behaviour by the threatened Leuciscidae Squalius alburnoides (Steindachner, 1866) at the Guadiana River basin (Portugal).

Squalius alburnoides (Steindachner, 1866) is an endemic threatened species from the Iberian Peninsula. Here, we report the first observations of intraspecific cleaning behaviour in isolated summer pools in the Guadiana River Basin (Portugal). We found that focal S. alburnoides solicited cleaning by adopting an immobile tail-stand position known as 'posing' which immediately signalled a response to a few conspecifics that approached and inspect them. Our study expands the list of "cleaners" in freshwaters, giving emphasis to the importance of mutual positive behaviour within an endangered species, particularly when facing seasonal disturbance. This article is protected by copyright. All rights reserved.