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Match Group, a subsidiary of IAC/InterActiveCorp and the undisputed shark in the online dating pond, just swallowed another fish: Today, the global operator of dating sites including Match, Tinder and OKCupid, announced that it will acquire PlentyOfFish for $575 million.

Vancouver, Canada-based PlentyOfFish was launched in 2003 by Markus Frind, and currently has more than 3 million active users, according to its website.

Meanwhile, Match Group -- which in addition to big names such as Match, OkCupid and Tinder, includes smaller dating sites like HowAboutWe, SpeedDate.com and OurTime.com in its roster -- has a 22 percent share of the $628.8 million dating app marketplace, according to a report from IBISWorld. In 2014, Match Group generated revenues of $897 million, representing almost 30 percent of IAC's $3.1 billion in total revenue.

Related: 6 Dating Apps That Are Putting a Fresh Spin on Finding Love

In June, IAC announced that it is preparing its dating service business for an IPO.

In general, online dating sites and apps are becoming increasingly popular with the American public. According to a 2013 Pew Research Center study, approximately 11 percent of American adults have used an online dating site or a mobile dating app, and market research firm IBISWorld predicts the dating industry in the U.S. will grow at an annual rate of 4.2 percent from 2014 through 2019.

"As more people than ever use more dating apps than ever with more frequency than ever, PlentyOfFish's addition both brings new members into our family of products and deepens the lifetime relationship we have with our users across our portfolio," Sam Yagan, Match Group's CEO, said in a statement. "I look forward to working closely with Markus and extending the company's impressive growth trajectory."

Match Group said it expects the acquisition to close in the early fourth quarter.

Related: The Bizarre Ways Niche Dating Services Are Pairing People Off