Light and heat are very important factors in an aquarium. Since it is an artificial environment, it is best to simulate natural conditions as much as possible to avoid having its inhabitants sicken and even die. For most people, having an aquarium means putting in the right water, providing the right food, and setting up a filtration and pump system that keeps the water that the fish breathe clean and fresh. While these are important factors themselves, the failure of most aquarium owners is to overlook the fact that lighting and heat are just as important to fish as the other things mentioned.
Lighting is extremely important because most fish except for deep water ones are used to seeing the sun, and it’s a fact that, like any other animal, part of the nutritional needs of fish are physiologically triggered and released by exposure to sunlight. While admittedly not as high as the needs of non-aquatic animals, it is still there.
Light sources come in a variety of types. One of the most common and popular types are fluorescent lighting. Fluorescent lamps are cool, inexpensive, easy to maintain and replace, and consume low power. For most aquariums, this need is enough.
There are also classic incandescent lights, which consume a bit more power but provide brighter, if harsher, lighting. These also run hotter than fluorescent lights, and are better suited for raising tropical fish, which naturally would be more comfortable in brighter and more temperate surroundings.
Compact lights on the other hand, consume the least power and generate the least heat, but also produce the least illumination. They are best suited for people who want to raise deep water fish or other breeds which prefer darker and cooler waters. However, if your aquarium has a high number of aquatic plants as well as fish, then you’ll probably need a metal halide light.
Metal halide lighting mimics sunlight at a low intensity level, roughly that which would breach the surface of water in natural environments to reach the bottom where the fronds and other aquatic plants are located. Metal halide lighting comes in a variety of intensities, and you should select one with a light and heat output that most closely approaches the natural environment of your aquarium’s inhabitants, both the plants and the fish. You should be careful with metal halide lamps, and avoid choosing one with a higher output than your aquarium’s needs; overexposure to sunlight on fish and plants which aren’t physiologically capable of handling them can be as unhealthy as no exposure to it at all.
Aside from the lighting system, water heater coils and even filters with built in heaters are recommended equipment for any aquarium. For those who are serious about raising their fish, there are even heaters with a temperature setting and thermometer. Avid fish raisers will have done their research, and will know the exact range of temperature their fish will be most comfortable at. For casual fish raisers, however, a general rule of thumb is to have a low power heater that keeps the water lukewarm even in relatively cold weather.
To go into further detail in heating; use two heaters for larger aquariums, one at either end to ensure even distribution of water temperature. This is very important, as if only one side of a tank is hot, then the other remains cold, it can cause some thermal shock when your fish swim from one side of the tank to another. To put it in human terms, imagine spending an entire summer day inside an air conditioned room, one cold enough to require wearing a jacket to keep the chill out. Then, after a while, leave the room once you’re become acclimated to the cold, and step outdoors into the blazing sun. THEN, once you’ve gotten used to the heat, jump back into the cold room. Obviously, this will eventually make most people sick. The same thing applies for fish.
Lastly, consult with your pet shop about the heater’s output. The larger the fish tank, the larger the heaters you’ll need to install. Heaters are measured not by their temperature output, but by their power consumption, which directly relates to their heating performance.
