I was born and brought up in St Helens, Lancs, and when I was a child (in the 1960s) the canal next to Pilkingtons sheet glass factory was reputed to have tropical fish in it, though I never went to look. The hot waste water from the glass factory was pumped into the canal. Where the water went in was too hot, then as it cooled off further away from the inflow it was just right for tropicals. The fish were supposed to have come from a shop that had gone bust.
For those residents of St Helens too young to remember the sheet works, it was where Tesco now is.