His father, Inacio, didn't want to raise the children, so Bibiano and his siblings were sent to live with their aunt in the Amazon rainforest, by the Ituxi River.

However, Bibiano caught malaria during their stay in the rainforest and his father was alerted to bring him back to Manaus for treatment.

[6] At the age of 13, Bibiano was introduced to BJJ, but coming from a poor family he was unable to pay for training.

In his second professional fight, Fernandes lost due to a doctor's stoppage to Urijah Faber in a King of the Cage event in Nevada.

[7] After dominating the first 2 minutes of the round, even taking Faber's back, he was reversed and received a barrage of elbows that opened up a deep cut on his forehead.

[8] After losing to Faber and Yamamoto, Fernandes won four consecutive fights before entering into the DREAM Featherweight Grand Prix.

[9] After defeating Warren by first round armbar, Fernandes' fight against Takaya was very close, and he won by split decision.

At Fight For Japan: Genki Desu Ka Omisoka 2011, he defeated Rodolfo Marques via unanimous decision in the semifinal round.

Fernandes next fight was at ONE FC 9: Rise to Power against Koetsu Okazaki for the Interim ONE Bantamweight Championship.

Fernandes next fought at ONE FC 11: Total Domination against Soo Chul Kim to unify the ONE Bantamweight Championship.

[20] In his fourth title defense, Fernandes faced Kevin Belingon at ONE Championship: Dynasty of Champions on January 23, 2016.

[21] Fernandes fought Kevin Belingon for the second time at ONE Championship 78: Heart of the Lion on November 9, 2018, in a title unification bout.

[23] He won the bout via disqualification when he could not continue after Belingon landed an illegal elbow to the back of Fernandes's head, once again regaining the bantamweight title.

[31] At weigh-ins, the pair failed to make weight in the bantamweight division and agreed to compete in the 153.25 lbs catchweight.

Fernandes returned to Brazilian jiu-jitsu competition at the IBJJF Pan Championship 2024, in the Master 3 featherweight division.