U modre ruze is as far as you can get from a river-related theme, but it's got a very nice atmosphere (usually with live music) and very good food and service.
I have been reliably informed, however, that this is not the ideal place to wow a 19-year-old Czech girl with.
And for some reason the mineral water is incredibly expensive (I think it cost about €8 as compared to the €14 they charged for a massive meaty skewer served as a main course with mashed potato, veggies and gravy; the wine wasn't too expensive either).