If that is the ambient (room) temperature, then the tank temp should be around 80 depending on the size of the tank, and you should be fine. Just make sure to have enough surface agitation to keep the water oxygenated as the warmer water becomes the less oxygen it will hold. If you have an open tank, then you could put a clip-on fan on the rim blowing at the surface of the water to help with this. And, of course, they do sell aquarium chillers just for this purpose.