Assistant coach Todd Richards will be Arniel's replacement, on an interim basis, for the rest of the 2011-12 season.
Richards, who joined the club as an assistant coach on June 20, 2011, will make his debut behind the Blue Jackets bench on Tuesday when the club visits the Chicago Blackhawks.
This is the first time Richards has taken over behind a bench in the middle of a season at any level.
"It's all new territory," Richards said. "It'll be different, it'll be a challenge."
Howson said he felt like his team was turning things around after missing James Wisniewski for the first eight games due to a suspension and assorted injuries, but the team's play of late sealed Arniel's fate.
"I divided our season into three parts," Blue Jackets' GM Scott Howson said. "The first part, we had a tough start. I didn't think it was a fair basis of evauluation because of the Wisniewski suspension and all the injuries. Really, if you look at our record from the middle of November to the middle of December, it was really good. In the 11 games since then, we've only had two wins and our play seemed to be regressing, so I thought it was time to move the team in a new difrection."
Richards, 45, compiled a 77-71-16 record as the head coach of the Minnesota Wild from 2009-11. Prior to joining the Wild, he served as an assistant coach with the San Jose Sharks in 2008-09 when the club compiled an NHL-best 53-18-11 record. Richards spent two seasons as the head coach of the American Hockey League's Wilkes-Barre/Scranton Penguins from 2006-08, compiling a 98-49-13 record and leading the club to the 2008 Calder Cup Final.
The dismissal of Arniel was announced less than 24 hours after the Blue Jackets dropped a 7-4 decision to the Ducks in Anaheim.
"I really made up my mind on the weekend that we had to make a change," Howson said. "I flew out here (to Anaheim) on Saturday and didn't want to do it on a gameday."
Arniel, in his second season with the Blue Jackets, had led the team to 11-25-5 record this season. At the season's midway point, Columbus, in last place in the League, has just 27 points and is 20 points out of a Stanley Cup Playoff spot in the Western Conference.
Arniel, 49, finishes his Columbus tenure with a 45-60-18 record. He was the fifth coach in Blue Jackets history.
He is the seventh NHL coach to be fired this season.
"Todd's got some experience as a head coach," Howson said. "He'll bring a fresh approach and new voice and we'll just try to move it in the right direction."