When you decide to have pet fish, you’ll need an aquarium heater. Fish aren’t really cold blooded like some people think; they just can’t maintain their own body temperature. In their natural environment, water and sunlight provide the warmth they need.
Even if the room where you keep your aquarium is comfortably warm to you, the chances are good that it is too cold for your fish, especially since water is harder to heat than air. So for your aquarium, a heater will provide the heat your fish need to thrive.
Generally, your fish will be healthy and comfortable in water that is kept around 79 degrees Fahrenheit. You want to keep the water temperature as constant as possible. Fluctuating temperatures lead to stressed fish, and it isn’t a big step from stressed fish to sick fish.battery aquarium heater
Getting The Right Size Heater
Aquarium heaters are rated by watts, for example 75 watts, 150 watts, etc. The rule of thumb is 5 times the number of gallons of water in the aquarium for proper heating. So for a 25 gallon aquarium, you will need 5 times 25, or a 125 watt heater. If your aquarium is big, two heaters may do a better job than one. In these cases, divide the total wattage you need in half, and buy two heaters of the resulting lower amount. For example, a 50 gallon aquarium needs 5 times 50 watts of heating, or a 250 watt heater. Instead of buying one 250 watt heater, you can use two 125 watt heaters.
The other thing that is good about having two heaters is that if one fails, the remaining heater will keep the water temperature fairly even until you can get another heater. This is really helpful when you have a lot of money invested in the fish (or other animals). In fact, if you have a lot of money invested in fish, it may be a good idea to have a back-up heater on hand just in case.
Speaking of heat, whatever kind of heater you use, you will want a separate thermometer to check the water temperature. This is your early warning system for a heater that is going bad or that something is happening in the tank that needs attention.
Now, on to the heaters.
Immersible Heaters
The most popular and least expensive type of heater is called a immersible heater. These are generally tube shaped, and made from glass, plastic, or aluminum. They have a control at the top for setting the temperature and usually have a built-in thermostat. They are positioned so that the top of the control of the heater is above the waterline while the cylindrical part that does the actual heating is under water. Placing these near the area where the water circulation begins or is strongest will help keep the proper temperature throughout your tank and avoid hot spots.
There are some versions of immersible heaters called submersible heaters. These can go entirely underwater. Submersible heaters are also effective and inexpensive. They are a little easier to camouflage if that is a big issue for you.
Other Heater Styles
There are two other styles of heaters that you may see online or in stores. They are the substrate heater and filter heater.
The substrate heater is installed below the substrate, that is the rock, gravel, or sand you are using in your aquarium. This kind of heater produces very even heating and plants love it. In fact, these are the most popular style heaters in Europe. The downside of these heaters is that if you have to repair or replace them, you’re going to have to take your entire aquarium down to get to them. So this is a good choice for installation in an initial set-up, but a lot more cumbersome to install in a tank that is already up and running.
A filter heater is a special heating unit that is placed inside the filter itself, so that the water goes back into the tank warm and clean. These heaters aren’t very common and can be expensive.