Is there a special training to be an opera singer?

Yes. it takes special training to sing opera.

Years ago, I was in Sam Goody's store in NYC, where headphones hung from a wall would allow you to hear samples.  There were 3-5 long haired biker/ headbangers taking turns.  The last one stopped headbanging - song must have ended - then got a look of unspeakable horror on his face.  His friends motioned to pass the headset - each took a turn, and left in seconds.  I picked up the headphones, and looked at the playlist.  It was Michael Bolton trying - and torturing - Nessun Dorma by Puccini.  This revolting experience is still an earworm for me.  So yeah - singing Opera well requires specialized training - not a raspy working class rock voice.  So thanks for waking up my earworm again . . .  I will have to wash it out with some Jussi Bjorling.

Anyone can sing whatever they like in the shower. If you want to get paid for singing opera you will need training and practice and luck; a lot.

If you want to do it in your basement, you won't need any training.  If you want to do it for an audience, you'll need a whole lot of training.  Opera snobs... sorry, fans are all about who you trained under.  I said snobs because I don't think there are any casual opera fans.

I can't stand the stuff myself, but I can respect opera.  It's an extremely technical flavour of music, kind of like the Kung Fu of singing, and everything is all about doing it perfectly.  It doesn't even have to sound good to impress opera fans, it just has to follow all the rules.

If you want to be technical, no. No training is required to sing an opera - you just have to sing. There are, after all, plenty of awful amateur operatic societies out there.

However to sing *classically* - which is what most operas require - does require training. You do not use your voice in a way that comes naturally to people.

Yes there is special training.

Yes, there is.