SMF Schramberg? Glazed Fish Dish

I found this gorgeous dish in a charity shop. It has SMF Schramberg painted on the back, but no makers mark or anything, so I don't know if it's genuine...I'm also clueless as to its age.
But it's so lovely. The colours are so vibrant and it's really heavy (weighs nearly 4kg). I also love the thick glaze with what appears to be glass embedded in it....it reminds me of sweeties for some reason!