"We take these allegations very seriously," an MTV spokesperson said in a statement. "We're working with Critical Content, our third-party production company, to conduct a thorough investigation and we've put a pause on shooting until the investigation is completed."
CNN has reached out to Critical Content for comment.
The investigation comes days after a former guest on the reality show posted videos on YouTube, alleging she was the recipient of sexually charged language and that she was repeatedly asked about her sexual orientation.
CNN has reached out to the woman for further comment but has not verified her allegations.
"The behavior described in this video did not happen," Schulman said in a statement to CNN. "I'm fortunate that there are a number of former colleagues who were present during this time period who are willing to speak up with the truth. I have always been transparent about my life and would always take responsibility for my actions -- but these claims are false."
Schulman, 33, has been the co-host of "Catfish" on MTV since 2012. The show is based on his and producing partner Max Joseph's 2010 documentary of the same name.
"Catfish" follows Schulman and Joseph as they help people who believe they've been duped into having a relationship with a person they met on the internet who is not who they claim to be.