When you are setting up your new aquarium, the first thing on your mind is not going to be the temperature. You are going to be thinking about issues such as water quality, compatible fish, and proper filtration. But the fact is that water temperature is a very important aspect that contributes to the overall health of your tank and your fish.
You may or may not be aware of this, but stress reduces the natural abilities of your fish to fight off diseases. So the job of the aquarium owner is to reduce as much of the stresses on their pets as possible. Temperature extremes as well as fluctuation can create a great amount of stress on the inhabitants of your tank. You need to avoid he temperature going too high, too low, or any great fluctuation. The temperature of your tank should be in the 75-77 degree range. If the temperature goes about 80 or below 72, you are setting yourself up for aquarium disaster. If the tank temperature goes too high, you will find an increase in algae growth, and your fish will become highly agitated, and expend much more energy than they should. If the temperature in your tank goes too low, your fish will become extremely lethargic. Either extreme will give your fish higher chances of getting sick.
Fluctuations in temperature are also dangerous, especially if they occur rapidly. Keep in mind that fish are cold-blooded animals, so their body temperature is regulated by their environment, so even a change of a few degrees can be hard o them. This is why you introduce new fish into the aquarium by floating the bag in the water for a while, allowing the water temperatures to become equal.
One thing to do to help keep your water temperature constant is avoid placing your tank near drafty areas, like near windows or vents. Second, buy a high quality thermometer. The type that stick to the outside of the tank are not ideal, as they give false reading easily. Try to find a thermometer that will be submerged in the water. These thermometers usually indicate the range that is ideal, but keep in mind that fluctuations even in the ideal range are dangerous.
The next thing you will need is a heater. You can purchase an aquarium heater wherever you purchase your other aquarium supplies. Before adding fish to your aquarium, take a few days to get the heater on the right setting. You may find that you need to adjust the temperature a few times before it regulates into the correct range. Avoid adding fish until you have a constant, appropriate temperature in your tank.
Keep in mind that when you do water changes in your tank, it will effect the water temperature. It is a good idea to allow your water to reach room temperature before adding it to the tank. This way, the change in temperature from the new water is not as drastic. Check your water temperature on a daily basis. If you find it is not in the correct range, adjust your heater, or purchase a new one. While it is not the most entertaining part of owning an aquarium, maintaining a constant water temperature is extremely important!