As with people fish thrive when kept in an environment as close to their own as possible. For this reason aquariums should be carefully structured to imitate the natural environments of the species it is home to as closely as possible. Even if it is not possible to duplicate exactly the living conditions found in the deep blue the fish will benefit from the effort.
Fish are also very adaptable creatures. It is what allows them to live and thrive in captivity when many other marine animals are unable to make the change. The fish will adapt to the environment around them and learn to live in the conditions of their tank. It is important that these conditions remain as constant as possible. As in nature a tip in the balance of the elements in an aquarium can bring with it devastating consequences. It is important that changes in the aquarium environment be few and far between.
This is generally a very simple matter until the time comes for the water in the tank to be changed. In nature the water in the ocean is constantly cycling; therefore, the water never has the opportunity to become stale and overloaded with elements that will have a negative impact on the well being of your aquatic friends. Since this is not the case in an aquarium even with an excellent artificial filtering system and organic filtering methods combined it will still be necessary on occasion to manually clean the tank.
The water with which you replace the dirty water in the aquarium should be as close as possible to the water that was originally filling the tank. What this means is that if you opted to buy a pre-made saltwater mix when you started your tank you should continue to use that same pre-made saltwater mix. If you made your own saltwater you should use the same type of sea salt in the same proportions that you used in the beginning. If you opted to transplant ocean water or purchased filtered ocean water you are going to want to use that same type of water when you make the change.
Water in aquariums should be changed every couple of months, more if you happen to notice that wastes are beginning to build up. This will be evident by the hazy look the previously clear water will take on and the obvious accumulation of waste at the bottom of the tank. Be sure when you change the water you also clean the components of the tank and the inside of the glass itself. Putting clean water into an empty tank is along the same lines as putting clean clothes on a dirty body-there is little point.
By keeping your tank clean and the conditions as constant as possible you are giving your fish the best possible chance to thrive in their artificial environment, guaranteeing that you will be able to enjoy their beauty for a very long time.