The strong decline of freshwater fish species in Europe implies that further ex-situ conservation plans should be implemented in the near future. The present study reflects our experience with the Pyrenean sculpin (Cottus hispaniolensis Bacescu-Mester, 1964)—a small cottid endemic to the Hispano-French Garona River basin. In recent years, the Spanish Pyrenean sculpin population has reached a limit situation. Because of that, the non-profit association ADEFFA—with support from the public administration—started the first captive breeding program for this species in 2006. Fourteen years later, this study presents the results and evaluates the different steps of the program, with the aim of discussing and improving the ex-situ conservation plans for this and other cold freshwater species. There is a description and a comparison between six consecutive phases during the captive breeding process: nesting behaviour, courtship, egg fixation, parental care (incubation), hatching and survival during juvenile development. The purposes of this project are to: (1) identify the most determining phases for a successful captive breeding; (2) identify the factors that had a major influence to the success of the critical phases; and (3) increase the number of the offspring. This study is based on thirty-three wild individuals collected from Garona River (Val d’Aran, Spanish Pyrenees). During the program, twelve couples spawned in captive conditions, with around 2300 eggs laid. Eight couples bred successfully, with 751 hatched individuals and 608 juveniles reared. The analysis of each step of the captive breeding does not reveal significant differences between phases, so it can be concluded that they are all critical at the same level. In the literature, similar study-cases of captive breeding programs identify incubation and survival phases as the most critical. Consequently, the management made for this project has probably allowed to overcome in part the main impediments described in other similar programs.

Case summary A 5-year-old neutered male domestic shorthair cat presented with an 18-month history of facial tics, and progressive general ataxia, weakness, lethargy and anorexia of 2 weeks’ duration. MRI of the brain showed a well-defined heterogeneous hyperintense mass on T1-weighted and T2-weighted images, with central hypointensity in the rostral commissure and septum pellucidum, and perilesional hyperintensity in fluid-attenuated inversion recovery, suggestive of perilesional oedema. Gross examination in a transverse section of the brain at the level of the septum pellucidum revealed a 0.2 cm brown soft mass. Histopathological examination identified a biphasic neoplastic proliferation of mesenchymal and neuroepithelial cell populations. Fusiform cells were predominately distributed in bundles showing a high degree of anisocytosis and marked immune-positive reaction to vimentin immunochemistry, confirming a sarcomatous origin. Additionally, high numbers of astrocytic cells were identified by an intense immunopositive reaction to glial fibrillary acidic protein and negative reaction to oligodendrocyte transcription factor 2 immunochemistry. Vascular invasion of the neoplasia into the wall of a medium branch of the rostral cerebral artery was present (secondary Scherer structures). Based on these characteristics, the tumour was defined as a gliosarcoma. Gliosarcoma is a recognised astrocytoma grade IV anaplastic glial cell tumour with sarcomatous differentiation. Relevance and novel information To our knowledge, this is the first report describing a cerebral gliosarcoma in a cat including clinical, MRI, macroscopic and histopathological features and immunolabelling characteristics.