beavis, I don't think 80 will hurt them, but if they're meant for 72-77 then you might just turn the heater off completely till it falls to that level. Sometimes aquarium lights add alot of heat to smaller tanks so you might turn your light off to allow temp to fall. They can handle being a little cold alot better than being too hot though, watch them and if they start to swim crazily and fast they are in big trouble so take them out of the tank. All of my fish are old and I don't claim to be an expert, so I don't know how brand new fish would react to water changes, but doing a partial water change could reduce the temp.

If its an adjustable heater just turn it down a couple notches. Turn the heater down a notch or 2 until the indicater light goes out(if equipted). Keep an eye on the light and temp. Make sure the heater doesn't kick on for more than a few seconds until the temp. goes down. Lights will deffinately heat up the water. If you have incadescent bulbs they can be changed for compact flourescent. Flourescent throws about 1/4 heat of an incadescent. You can raise the light fixture about 2" using blocks of wood, or something to allow air to pass thru. The 80F "shouldn't" do harm for a short amount of time, it really depends on type of fish. A partial water change with cooler water added slowly is an excellent idea. A little aquarium salt for stress is always good idea for new fish. Since you floated the bag it should have helped acclimate the fish and reduce shock.

Yes, it has an indicator light, I think i'll do that. Thank you!