If you kept goldfish at the upper end of their temperature requirements, and bristlenose at the lower end of theirs, then just about- they need water 22 degrees or higher according to Planwet Catfish- I usually aim for about 24, which would be the upper limit for goldfish. I know of people who've kept plecs with subtropical and temperate species but I've never seen bristlenose with temperate species so I'm not sure if there'd be any problems.
