The overflow from the Roman Baths discharges into the river having traveled underground for hundreds of yards in a stone gulley at the same rate as it has since the Romans built it almost 2000 years ago.
Fish love to swim around in the warmer water, especially in the Winter, but this year a couple of real monsters have turned up. Have a close look at the video and you will see one almost 3 feet long, lurking in the shallows as it filters out nutrients from the discharge. Thousands of minnows are thrashing around in its wake, doing the same thing. They are probably related.