It's „Kawia domowa” these days – them scientists ruining perfectly serviceable names, because 'original name was mistranslated from Spanish' or same such rot. ;)
The entire time I lived in Poland I never heard someone call it that. We have a one as well. Sometimes you can find people online call them by that, same in English, but it is just the scientific name.
I wish they would change some things like "weekend" though.
Yes, I know – it was meant more like a joke really, the very idea that people will change their language habits just because PAN changed the poor creature's name last year is a bit laughable… In fact, I had to use google to find out what they renamed „świnka morska” to, because I couldn't recall it. ;)
The way I understand it is that everything has a scientific name and a lot of things also have a "cultural" name. I've always felt like the scientific name is comparable to how stars are named. No one really calls them that, it is mostly meant for efficient study and cataloging.