Zombie Fight is a Manga/Manhwa/Manhua in english language, Manhwa series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

As life gets harder, Ian pushes his emotions away and resists. His father's violence and debts increase ... Thee misfortune continued and his body became increasingly numb.
accidentally he walks through an illegal fight and receives an offer.
"If you get in the game, I will give you all the money on this floor."
His survival period begins, where he must survive in an illegal fighting arena