Although we usually think of cold water fish as simply "Common Goldfish", there are in fact quite a number of species native to more temperate regions which will live very happily at room temperatures. Nor is it fair to label Goldfish as 'Common', at least not in the derogatory way in which it is usually applied. Goldfish species, and the Carp family to which they belong, have for centuries been breed to produce a vast variety of colours and shapes to suit all tastes.
Many of the selectively breed species from China and the Far East were once considered so rare and valuable that they were regarded almost as state secrets, and severe penalties existed for anyone attempting to smuggle them to the west. Nowadays thankfully we live in a more enlightened world and many of these exotic varieties are available even here in the UK.
In addition to Goldfish varieties, there are numerous "tropical" species which have been 'incorrectly labeled' and which thrive in cooler waters. Perhaps the most notable example is the White Cloud Mountain Minnow from northern China. Almost always sold as a tropical species when in fact it does not like high temperatures, and will become stressed and lose it colours with water temperature above 24°C - 25°C.