Variances in Temperature OK?

[TortoiseAvenger]

My aquarium has slight variances in temperature from day to evening. It is on the second story of an air-conditioned (although old) house, and the air dosen't always quite cut it up here in the hot months. The temps flucuate between 77.5 and 79.5 depending on the time of day. The temperature changes (as far as I know,) are not sparatic, they gradually occur throughout a 24-hour period. One could assume that this is OK, since there must be temperature fluctuations in nature... lets not forget that fish DO live outside .

It's a 30G planted with Angelfish and Cories.

 

[Blinky]

The bodies of water that fish live in in nature are HUGE, and they don't warm up and cool down quite the same way, I don't think. If you can get a heater and set it to 79.5, when your house cools down the heater will kick in, and when the house warms up the heater will stay off, and your tank's temperature will stay at a steady 79.5.
Your fish might be okay, but the fluctuations might also stress them out. Also one day your house might get colder than usual, and if the temperature dips more than just a couple degrees (say if it dips 3-4F rather than just 2 degrees) you could be looking at an outbreak of disease.

 

[Bigguppy]

It's a crap shoot. You never know. It's best to regulate the temp with a heater.

 

[RioXingu]

If the small temperature changes you described in your aquarium were harmful to fish, very few people would be keeping them.
Large, rapid shifts in temperature are to be avoided.
Your situation sounds ok to me.

Bill in WI