I apparently havn't lived because I had to look up what catfished meant!!!! So my answer would be no and thanks for adding a new word to my vocabulary.

Yes, but usually it is really easy to spot, especially if they claim to be someone who should have a much better handle on writing, syntax, spelling. I don't care about that, I'm never going to meet them anyway. It is more annoying to me to actually decide to meet someone and then find out that they were not truthful about age, weight, interests, etc, etc. I don't get it because they know once they meet someone the jig is up and they appear as being untruthful.

It is as common as religion, all of them put together !

Yeah sort of. One girl put up a couple of photos, one of them was not her. Apparently it was a pic of someone a little bit famous I have never heard of and cannot remember. But they were so alike I would not have noticed if a friend had not pointed it out later. Wasn't a huge lie she really did look like the other girl.

I have encountered a ton of scammers, mostly on OkCupid. It is usually immediately obvious. One guy was particularly witty, so I played along for about a week. When I mentioned I am an atheist, he started preaching to me. At that point, I wrote,
“Based on your grammar and syntax, you are most likely in Ghana, Accra, specifically. You’re between 20 and 25, and are new at this scam thing. How did I do?” He confessed! I was dead spot on. 21, in Accra; I was his third attempt. He felt so guilty that he claimed I had shamed him into giving up the scamming business. He acknowledged that an atheist acted more godly than he had! He gave me what he said was his real name and photo. I told him to just be upfront and state that he is looking for a Sugar Mama. He was an articulate, good looking guy. After that, I didn’t bother replying to scammers. I just blocked them. I still hear from Edwin from time to time, though.

They've tried a bunch on match.com. And once on Twitter.

I've had scammers try to convince me, but no, I don't get emotionally invested much before I meet someone so it's not something that has happened to me. I'm sure I've talked to people who catfish, but I haven't fallen for it.

There are a lot of scammers.

Yeah, I ran into a few scammers, but not on here. I figured them out before anything embarrassing or expensive happened to me.

If you mean people using other's profiles, that seems almost more common than not on most dating sites, and most friend requests on Facebook are fake also.
It's usually some handsome, lonely military guy, who doesn't use articles and has verb tense confusion, as an Asian native speaker would.