Description : The HydroChange mooring dedicated to the temperature and salinity long-term monitoring of the Mediterranean deep water moored in 2003 in the Gulf of Lion central zone of Deep Water Formation (~42°N-5°E, ~2300m) did not surface as expected 2 years later because of the acoustic release malfunctionning. It was not until 2018 that it could be recovered, thanks to the Ifremer ROV VICTOR 6000, operated by Genavir. The video shows the ROV VICTOR descent, progression toward the mooring position, inspection of the mooring line and instruments, and the mooring release. Besides ancillary information that this video provides on deep fauna and bottom sediment aspects, it shows the unexpected -and never seen before- living biofouling on instruments and mooring line (~2300m, actinia). The longstanding efforts to recover the T and S(C) probe were rewarded by unique timeseries ot temperature spanning 2004-2015, and salinity spanning 2004-2011. Montage et infographie: Pierre Blanchard, PB Productions. Crédit images: IFREMER/VICTOR 6000. Drones and surface sequences: Stéphane Lesbats. Pictures: Olivier Dugornay, Michel Gouillou, Stéphane Lesbats.