The Spanish left-back arrived at the City Ground alongside Greek goalkeeper Stefanos Kapino, and fills the void left by Armand Traore's departure to Cardiff City.
His position has been something of a weak link for Forest since Dani Pinillos's exit at the end of last season, and several Reds fans are unsure whether Fuentes is an upgrade on his fellow countryman - and former Cordoba player.
Here's what they are saying about the signing...
Not the Spanish Left back I wanted, @DaniPinillos3 miss you Mate x— Harvey (@HarveyLawrence8) 8 February 2018
@nottmtails why oh why did they let pinillos go? Cult hero after the Derby goal, solid left back, miles better than Traore / Fox.— shinjay (@shinjay_) 8 February 2018
Last time we signed a free agent LB he became a fans favourite Dani Pinillos,hopefully this new LB is decent got good experience #nffc— ً (@Kieranffc18) 8 February 2018
Welcome to #NFFC Fuentes but I for one don't get why we didn't keep Pinillos— Sam Crawford (@s_redmist) 8 February 2018
Because he wanted a bigger wage and longer contract than we were prepared to offer, allegedly.— Woof Zip Criminal (@fritzromanov) 8 February 2018
He was a bit injury prone but I rated him. Hoping this Fuentes can do a bit.— Craig (@MrCraigH) 8 February 2018
Colback hadnt played all season until Fulham and was then man of the match. I don't know anything about him but it's low risk. Pinillos and jokic or whatever his name was were decent— Ryan Wise (@ryanwise94) 9 February 2018
He’s a better player than Pinnilos that so many crave mistakingly to have back at Forest— Terry Norman (@tjnnorman) 8 February 2018
Pinillos - who is back in English football with Nottingham Forest's Championship rivals Barnsley after a short-lived return to Cordoba - spent two seasons at the City Ground, but only made 35 appearances due to injury.
The 25-year-old - who has considerably less top flight experience than Fuentes, who had spells with Espanyol and Osasuna - scored his only goal for the Reds in last season's derby draw against Derby County.
Is Fuentes a good signing for Nottingham Forest?