Saltwater aquarium fish

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Thu Feb 7 19:13:13 UTC 2008


Light is one of the primary factor for life on out planet. When out planet was born and there were oceans on the surface, almost immediately life started on out planet. The main factor was the water as the environment and the sun as the source of the energy. In salt water aquarium you have to regard this fact. All creatures (maybe except of fungus) will need light.

I should probably start with impacts of the light on the living organisms in your tank. If you want to have anemones and green salt water plants, you have to know one thing; They will grow to the places where the light is. So if you choose a place for the aquarium which has a plenty of light from the outside of the tank, they will not grow as usual, but towards the aquarium glass and such situation may affect the look of the tank. This natural light can affect the tropical fishes too. Some are photosensitive and they use to feel sunlight on their backs, because in normal condition the brighter light comes from the surface. However, if the most bright light comes from the side, they will swim sidelong. So the main thing is to choose a good position for the tank. It should be maybe in the darkest place of the room where is no sunlight through the day. But of course, where the temperature is stable, so do not choose a place near doors or so. Another very important factor is that fish need the night and day period. Some fish will eat trough the day, some only at night, some even before sunset or sunrise. And the same it is with breeding. Some species breed only during nights and some only during daytime.

Algae and light

Another good result of the light is algae. It is the food for many salt water aquarium fish, so you should keep a lot of algae in the tank, especially if you want to raise algae-eaters. Most algae-eaters are omnivore and salt water algae is very important green food for them which they can eat between feeding times and these fish will spend their time with something more creative than just swimming around and doing nothing. Salt water algae require a lot of aquarium light for their growth. Light enables one special process in the bodies of plants — photosynthesis. It is a process when water and carbon dioxide convert themselves into oxygen and glucose, which is the building material for algae and plants too. This glucose is the reason why the fishes and some aquarium creatures eat algae. Glucose is energy which keeps the green eating organism alive. You can also say that you don’t want any salt water algae in the tank because it looks ugly, but you have to think about what is more important: your fish’ health or the look of the tank. Also you can choose fish which do not eat algae. And maybe if the algae will not grow very quickly, the fish will eat it sooner than it could be spotted. Another important role of the algae and green plants in the aggregate is that they create oxygen and process the fish excrement so they keep the NO3 level low and make the water safer for the fish. But you have to be careful with the aerator. Do not shut it down through the night, because plants breath oxygen at night too and the fish could not have enough air for themselves.

Not only fish and plants are affected by the light, but also micro-organisms. They are also an important part of fish’ feeding habits. Also they play role in the water chemistry balance. Some of them can produce many toxic wastes, especially those anaerobic, which reproduce at dark. So if you don’t have salt water aquarium lights in the tank, these micro-organisms can produce so many toxic wastes which will kill your fish.

Also there is another role of salt water aquarium lighting. You want to see your fish, you have to see how they feel, if they are not sick, if they eat and so on. The process of choosing the light is important also thanks to the fact that various fishes may look differently with two or more different lightings. It depends on what colour the light emit. The light should be turned on for about 12 hours a day. In tropical salt water aquarium it can be more, but in cold water aquariums it should be less and in such tanks you also should simulate seasons of the year. In the summer season you should provide more light than in the winter season. Another aspect of the thing which you should know is, that only shutting down the light is not a good idea. The fish can be scared and can injure themselves. You should damp down the light down in the night and there should be similar mechanism for mornings too. This is a good choice if you have fish which eat or breed during sunset or sunrise. Or you can shut the aquarium lights down in the tank and only after a few minutes shut down the light in the room too. Another chance is to use blue light tubes through the night. They require only a couple of watts and have intensive dark blue light, which is just sufficient to see fishes in the tank. This blue light simulates the moon shine and it is recommended for growth of corals.

Choosing the light for your marine aquarium

When you are choosing salt water aquarium lights, you have to make a compromise between what you want and what your fish need. Fish may live in different depths of the sea, and in different depths there is different amount of light. Also tropical salt water fish will need more light than fish from the colder regions, because in the warm waters there is more light, except the fishes and creatures which live in rocks and caves. And don’t forget that you should keep fishes only from one region, so you can provide the best conditions for all of the fish. But you should bear in mind that more light you have in the tank, much more algae you will see there. If you want to have only small amount of light, you should choose only one, for example, fluorescent tube. But for more light you should have more of them, because the strength of one fluorescent tube is limited. And how can you know how much light you should have in the aquarium? You definitely need hiding places. If fish are rather in the caves, you have too much light in the tank. Maybe you should start with proportion one watt to one litre of the water. Then you watch how your fish react and how do you like the tank. It the fish seems OK, but you would like more light, intensify the light a bit.

The ordinary light bulb is not a good choice for any salt water tank. It is not effective because most of the energy transforms into heat and the heat may overheat the tank and disrupt the balance. I don’t even have to mention that you will have to use an aquarium chiller and it will spent even more energy during the warm periods of the year. That is the reason why low temperature fluorescent tubes are the best choice, even if ordinary light bulbs are cheaper. Another advantage of fluorescent tubes is, that they last for longer time and are safer, because the ordinary bulb may implode and the pieces may hurt the fish. Then you can choose from many variants of the tubes. You may choose tube with long or short wavelengths. Long waved are red-orange and short waved are blue, violet and indigo. You should not use normal tubes which you have in you room as a light. You should buy these products is aquatic shops only, or specialised pet shops, because only those can provide a light, that is suitable for plants and fish. Ordinary light tubes which you use in the room give only white light and it does not simulate the sunshine as good as those special tubes. It is truth, that the tubes are not as bright as ordinary bulbs, but most aquarium hoods have place for more tubes. Especially those which you buy with the aquarium. Usually the bigger the tank is, the more place for tubes there is. Then you can use aquarium spotlights too. They can be used bulbs in special spotlights which hang above the tank. It is a very useful thing because the aquarium light does not come in contact with the salt water and the light is safe because the water will rust the light if it is not waterproof. So if you use hood, it also has to be waterproof, or you can use a glass under the light. The spotlights can have a very intensive light so they can be used for deep marine tanks. But you should be careful when you are using such strong light. Very strong salt water aquarium light may harm some fish, especially those which like shadow. Also strong light can warm up the water, and can destroy the stable temperature, and the warmer the water is, the less oxygen there is, so you also will need a strong aerator.

The position

Also, you should choose the position of where the marine aquarium light should be. The position of the light is very important. The best position for a bulb is in the front of the tank, but then you have to count with algae on the front aquarium glass too and the algae will disable the view into the tank, unless you want to see how are your fish eating the salt water algae. Then you can install the light on the sides of the tank, or at the back of the aquarium. This position will not provide enough light for a good view, but the algae will not grow on the front glass and fish will have enough light too. Maybe the best position for the salt water aquarium light in a tank with salt water algae-eaters is above the salt water decoration and rocks, so the algae will grow on them. Especially if you have larger rocks in a reef style, where the largest stones are in the back site and the smallest in the front. In this case you maybe should situate the light above the middle of there rocks.
Document created on Thu Feb 7 19:13:13 UTC 2008
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